Gallas, who was at fault for two of the goals, says the defensive efforts of the North Londoners was not good enough and he is looking for rapid improvement in their next outing.
"I'm very disappointed because even if I think we didn't start the first half very well, we came back well in the second half," he told Spurs TV.
"We equalised and we scored the second goal, and then I think we made so many mistakes.
"We could not keep the ball in front and it was difficult for us because they had a lot of chances, and they had the occasion to equalise and then to score the third goal. On all the goals we conceded I think we made a mistake.
"When you play against Chelsea you have to be strong for 90 minutes, and we made so many mistakes. We didn't keep the ball very well and they started to play in our half again. They had some chances to score, and in the end we lost 4-2.
"We have to put this behind us. It's difficult to accept it, especially when you play against Chelsea - when it's a derby you always want to win. But we have to forget that game and think about another one."