"I'm not saying we weren't ready for the game because I think we were, but sometimes after a huge game in the Champions League it's difficult to find the same level of motivation for the following game.
"In fact, what we needed was an even higher level than we had in Milan. We all have to understand that quickly because time is running out this season."
Gallas, who won two titles with Chelsea, added: "If you look at the table, I'm not saying we are in trouble but we have lost our lead so it's not all in our own hands.
"We have to think about ourselves, not look at the table, and we have to win every game."
