Although going out of the competition before Christmas is a new experience for the Frenchman, he is backing the Reds to rally on the back of such a disappointing defeat.
"If you play for Manchester United, you have to be strong," he added. "I think the gaffer knows the players will get back because they've got a strong mentality. For six years, as I said, I've never been out in the first round so it's a new experience for us. We have got to get back and get focused on the Premier League as that's the target - to win the Premier League.
"It will be more difficult for us [with the Europa League commitments] but we deserved it with the way we played. We deserve to play on Thursday and Sunday.
"But we are Manchester United. Today is a really bad day for everyone - the fans, staff and players. We must make sure we don't throw the season away. We still have things to win and must make sure we play with heart. The fans deserve something better than us throwing away the Champions League."