Real Madrid coach José Mourinho warned his players their work was only half done after they opened a 3-0 lead over Galatasaray in their Champions League quarter-final first leg.
Goals from Cristiano Ronaldo and Karim Benzema set Madrid on the way to victory at the Bernabéu before Gonzalo Higuaín's header extended the advantage.
Mourinho will not take the second match lightly, and said: "They will give their all to try to pull off a historic result and I have enough experience to know that although I am happy with the result, the tie is not over. I have to convince my players to believe that too."
He added: "The team played well and produced a professional and balanced performance. We defended well and were dangerous on the counter-attack. They knew that at this stage of this competition that matches are decided by the slightest of margins, and we were concentrated and played with humility."
The wide margin of victory left Galatasaray coach Fatih Terim fearing the worst, saying: "After losing the match 3-0 we need a miracle but in Istanbul we will try to play well and win the match."
Mourinho added: "They need a miracle but miracles happen in football, the history of football is full of miracles, why can they not dream of a miracle?"
Terim criticised referee Svein Oddvar Moen's performance, above all his decision to book striker Burak Yilmaz instead of awarding a penalty following a challenge from Sergio Ramos late on.
"Maybe the name Real Madrid affected Galatasaray and the referee did not have courage," Terim said. "The referee made many mistakes. Burak was fouled, everyone saw it except for the referee, but despite everything there is nothing we can do, the result is there for everyone to see."