"You can guarantee that if we win against Lyon the mood will change, and if we can win against United, the mood will be totally different," said the boss.
"When you are not winning, to play another game quickly and have the opportunity to change things is the best thing.
"We will try to win and then everything will be different.
"I have a lot of confidence because we are a good team. We have some problems with injuries but the squad as a squad is good enough to win some games.
"A positive result would be massive for our confidence. The Champions League is a different competition and the players know the fans will be behind them, so it can be a big boost for us.
"The fans know when the team needs support and they are behind us. Our fans are the best in the world, and when we need something they are there pushing us."