The statistics said it all really. After 853 matches and 22 years, Manchester United had let a two goal lead slip and lost. For years, United fans had been used to their team performing remarkable acts of escapology and asserting their authority once they assumed a commanding position. However, against Nigel Pearson's Leicester City, the tables had been turned. In one of the most surreal and extraordinary Premier League games you're ever likely to watch, United went from being 3-1 up after 57 minutes and cruising, to finding themselves staring at the ignominy of a 5-3 defeat.
This wasn't the Manchester United we had come to know and love/hate (depending on your allegiances of course). Louis van Gaal could only watch in horror from the dugout in the King Power Stadium as their cruise control turned into an absolute catastrophe. In 21 chaotic minutes, United conceded four times - the first time that had ever happened. Tyler Blackett had been sent off for a foul on Jamie Vardy that effectively ruined the young centre-half's chances of making it in this van Gaal system.
While United furiously protested Mark Clattenburg's decision to award two penalties to Leicester during the game, Van Gaal firmly pointed the finger of blame at his players. In the Dutchman's eyes, his players should have been able to harness the growing momentum of their opponents and see out the game 3-2. But they capitulated in the most comical circumstances and the post-mortems were stinging in their analysis of just how dishevelled and headless United's defending had been.
It was a most chastening experience for United, but one they have certainly learned from. It may have taken time, but United's back four now looks to be the most solid and efficient element of Van Gaal's United - and there has been a series of factors contributing to a sustained period that saw them go just over 10 hours without conceding in the league, eventually ended by Troy Deeney's penalty in the 2-1 win over Watford.
Firstly, Van Gaal knew the job of making United defensively sound once again was buoyed massively by retaining the services of David de Gea over the summer. Although the deadline day debacle reflected poorly on both United and Real Madrid, it secretly had Van Gaal smiling. It became abundantly clear that Sergio Romero, signed for free from Sampdoria in the summer, wasn't going to cut it and reinstalling the Spaniard into the starting lineup has given United that sense of security, illustrated most recently by de Gea's outstanding reflex stop after Almen Abdi's shot ricocheted wildly off Chris Smalling's head.
Speaking of which, Smalling has been at the epicentre of United's defensive resurgence this season. The club have only conceded nine goals in 13 games and it's largely down to his omnipotence at the back. Last year, Smalling only managed 21 starts in the Premier League through a mixture of injury, indiscipline and falling out of favour. Now, he's the first player on the teamsheet every week and should his current zenith of form continue, United may just be in with a shout of the title.
It could be said, however, that they face their biggest challenge yet in coming up against the rampant Vardy, who will be looking to break Ruud van Nistelrooy's record of scoring in ten consecutive Premier League games when the two sides meet again on Saturday evening in a top of the table clash. The last time that happened was in 2000, when United travelled to Filbert Street and knocked the Foxes off their perch with a comprehensive 3-0 win.
Vardy has been the headline-dominating star of Claudio Ranieri's glittering array of attacking talent. With the likes of Riyad Mahrez, Leonardo Ulloa and Jeffrey Schlupp all enjoying productive seasons, United's defence will be stretched and tested to the extreme once again. It's fair to say that they've come a long, long way since crumbling at the King Power Stadium last September and facing Leicester again provides the perfect opportunity to definitively exorcise some ghosts.
Smalling recently revealed that United's impressive defensive record this season has come about simply because of graft on the training pitch. "We do a lot of tactical play, we play a lot of 11 versus 11s and, in terms of how the pitch is broken up, we know where as a front pair when to drop and how deep for us to go," he said.
With Leicester City's relentless and frenetic approach to attacking typified by the ceaseless running of Vardy up top, Smalling and his team-mates will need to remember their training ground education more than ever.
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