He told Arsenal TV: "The title is a dream and to get that dream you have to fight.
"We have to take it game by game, and we have to be ready for the fight. We know it will not be easy for us, and Manchester United will have confidence and if we want that title we have to fight.
"The defeat was very tough for us. We did not play well. We know we were not good at all.
"Everyone was disappointed and now we have to work and work again to see what we can do in the Champions League and the Premier League.
"We have to put the game behind us. On Wednesday it will be different as we are at home and we can play our game, but away we have to fight and we didn't fight on Saturday."