Barcelona's unbeaten start to the Primera Division was ended on Sunday night, as Athletic Bilbao claimed a deserved 1-0 victory at San Mamés Barria.
Iker Muniain steered home the only goal of the contest 20 minutes from full-time, as Barça slipped to a second loss in five days following their disjointed defeat to Ajax in the Champions League on Tuesday.
While the loss in Europe can be absorbed, defeat in La Liga is much more damaging with Gerardo Martino's men now level with Atlético Madrid at the summit on 40 points, three clear of a Real Madrid side who appear to finally be hitting their stride.
Stop crying your heart out: Neymar reacts to Barcelona's defeat
Nevertheless, Barça midfielder Sergio Busquets is refusing to get overly concerned by their recent results, saying after the Athletic defeat: "There's no need to be alarmed, we just have to carry on.
"We have to win the two (league) games that are left to play this year and learn both from our errors and the things we are doing well."
Athletic Bilbao 1-0 Barcelona
FBL-ESP-LIGA-ATHLETIC-BARCELONA(01 of43)
Athletic Bilbao's midfielder Ander Herrera (R) vies with Barcelona's midfielder Xavi Hernandez during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(02 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar of FC Barcelona reacts during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(03 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar of FC Barcelona reacts during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(04 of43)
Athletic Bilbao's goalkeeper Gorka Iraizoz celebrates his team's goal during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(05 of43)
Barcelona's defender Martin Montoya (L) vies with Athletic Bilbao's midfielder Mikel Rico during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(06 of43)
Athletic Bilbao's forward Iker Muniain (C) celebrates after scoring during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(07 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar of FC Barcelona is brought down by Ander iturraspe of Athletic Club during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(08 of43)
Barcelona's defender Martin Montoya (L) vies with Athletic Bilbao's forward Iker Muniain during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(09 of43)
Athletic Bilbao's forward Iker Muniain (R) vies with Barcelona's Chilean forward Alexis Sanchez during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. Athletic won 1-0. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(10 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar of FC Barcelona reacts during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(11 of43)
Athletic Bilbao's forward Iker Muniain (2ndL) celebrates after scoring during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(12 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar of FC Barcelona reacts during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(13 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar of FC Barcelona sits on the pitch among Athletic Club players during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(14 of43)
Barcelona's midfielder Sergio Busquets (R) reacts past Athletic Bilbao's French defender Aymeric Laporte during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(15 of43)
Athletic Bilbao's midfielder and captain Carlos Gurpegi (L) vies with Barcelona's Brazilian forward Neymar da Silva Santos Junior (R) during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(16 of43)
Athletic Bilbao's midfielder and captain Carlos Gurpegi (L) vies with Barcelona's Brazilian forward Neymar da Silva Santos Junior during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(17 of43)
Barcelona's Brazilian forward Neymar da Silva Santos Junior shoots during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(18 of43)
BILBAO, SPAIN - DECEMBER 01: Alexis Sanchez of FC Barcelona duels for a high ball with Mikel Balenziaga of Athletic Club during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(19 of43)
Athletic Bilbao's French defender Aymeric Laporte (R) tackles Barcelona's defender Martin Montoya during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(20 of43)
Barcelona's midfielder Andres Iniesta (L) vies with Athletic Bilbao's midfielder Markel Susaeta during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(21 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar of FC Barcelona sits on the pitch among Athletic Club players during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(22 of43)
Barcelona's midfielder Andres Iniesta (L) vies with Athletic Bilbao's defender Andoni Iraola during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(23 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar of FC Barcelona duels for the ball with Andoni Iraola of Athletic Club during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(24 of43)
Athletic Bilbao's midfielder Ander Iturraspe (Back) fouls Barcelona's Brazilian forward Neymar da Silva Santos Junior during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(25 of43)
Athletic Bilbao's forward Gaizka Toquero (L) falls past Barcelona's defender Martin Montoya during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. Athletic won 1-0. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
FBL-ESP-LIGA-ATHLETIC-BARCELONA(26 of43)
Athletic Bilbao's forward Gaizka Toquero (L) falls past Barcelona's defender Martin Montoya (C) during the Spanish league football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on December 1, 2013. Athletic won 1-0. AFP PHOTO/ RAFA RIVAS (Photo credit should read RAFA RIVAS/AFP/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(27 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar of FC Barcelona sits on the pitch among Athletic Club players during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(28 of43)
BILBAO, SPAIN - DECEMBER 01: Alexis Sanchez of FC Barcelona wins a challenge by Gazika Toquero of Athletic Club the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(29 of43)
BILBAO, SPAIN - DECEMBER 01: Sergio Roberto of FC Barcelona reacts on the pitch at the end of the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(30 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar of FC Barcelona duels for the ball with Mikel Balenziaga of Athletic Club during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(31 of43)
BILBAO, SPAIN - DECEMBER 01: Andoni Iraola (C) celebrates with his teammates Carlos Gurpegi (L) and Ander iturraspe of Athletic Club after deafing FC Barcelona at the end of the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(32 of43)
BILBAO, SPAIN - DECEMBER 01: (L-R) Cesc Fabregas, Gerard Pique, Xavi Hernandez and Andres Iniesta of FC Barcelona argue with the Referee Juan Martinez Munuera during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(33 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar of FC Barcelona is brought down by Ander iturraspe of Athletic Club during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(34 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar of FC Barcelona runs with the ball during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(35 of43)
BILBAO, SPAIN - DECEMBER 01: An Athletic Club wearing a Basque traditional cap covered by badges looks on during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(36 of43)
BILBAO, SPAIN - DECEMBER 01: Andoni Iraola (C) celebrates with his teammate Carlos Gurpegi of Athletic Club after deafing FC Barcelona at the end of the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(37 of43)
BILBAO, SPAIN - DECEMBER 01: Gerard Pique of FC Barcelona shakes hand wqith Athletic Club players at the end of the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(38 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar of FC Barcelona is shown a yellow card by the referee Juan Martinez Munuera during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(39 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar of FC Barcelona duels for the ball with Carlos Gurpegi of Athletic Club during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(40 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar (2ndL) of FC Barcelona is shown a yellow card by the referee Juan Martinez Munuera during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(41 of43)
BILBAO, SPAIN - DECEMBER 01: Pedro Rodriguez of FC Barcelona reacts after missing a chance to score during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(42 of43)
BILBAO, SPAIN - DECEMBER 01: Sergio Busquets of FC Barcelona is brought down by Iker Muniain of Athletic Club during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Athletic Club v FC Barcelona - La Liga(43 of43)
BILBAO, SPAIN - DECEMBER 01: Neymar of FC Barcelona duels for the ball with Carlos Gurpegi of Athletic Club during the La Liga match between Athletic Club and FC Barcelona at San Mames Stadium on December 1, 2013 in Bilbao, Spain. (Photo by David Ramos/Getty Images) (credit:Getty Images)
Teammate Andrés Iniesta felt his side were relatively comfortable until the goal, saying on his club's website: "We had the game under control, but the goal really hurt us. San Mames is always a tough place to come to.
"We put in a good first half and we played well at times after the break, but the goal really shook us and although we really tried, we couldn't come back."