The Blues are currently in fourth place, but are twelve points behind Sir Alex Ferguson’s men in the race for the Premier League title.
The Spaniard is looking for an upturn in results, starting with at Stamford Bridge this weekend.
“The whole squad is not content with our game at the moment,” he told Mirror Football.
“We are not functioning well enough in the Premier League and we need a quick reaction. That is our main objective.
“It’s normal that the manager (Villas-Boas) is not happy with the performances, but we know we can still improve on the pitch.
“You can never say anything is impossible in football. But at the moment the gap is too big between us and the Manchester clubs. There’s too many points.
“We need to reduce the gap on Spurs but to do that we need to keep winning – just win, win and win.
“That’s why the match with United is so important to us in terms of belief and morale – to beat the champions is very important and that’s the challenge for the whole squad. We are all very focused on this game.
“I don’t know why or the reasons, but Chelsea suffer more against teams who, in theory, are supposed to be inferior but in this league they are not inferior. But we do well in the bigger games.
“United are also missing players and it is very important that we improve and show our best level on the pitch,” he concluded.
By Gareth McKnight