The England international has only started two games for Mourinho this season, against Blackburn in the Carling Cup and Sheffield United in the Barclays Premiership.

Cole was outstanding for England in their recent friendly against Holland but Mourinho insists the former West Ham player does not need to impress him.

Mourinho said: “Joe is a victim of the injury he had. He had a big injury in our first friendly in America in the summer and after that he couldn’t train for two months.

“I gave him a game in the Carling Cup but he was still not at the maximum. Now he is a victim of Chelsea’s performances and results.

“It’s not easy for me to change the team when the team is playing so well but tomorrow he plays from the start.

“The opportunity is not to impress me or make me think he’s a very good player. I know that.

“He doesn’t have to impress me. It’s for him to do well for the team. He has played in all of our games in parts, but it’s easier to start a game than always to come on in the second half and he has a lot to give us.

“Last season he was crucial for our Premiership title and also for our squad. Joe at his maximum level is a very important player for us.”

Mourinho also confirmed that Khalid Boulahrouz would replace the injured Ricardo Carvalho alongside John Terry in defence and Michael Ballack would take the place of suspended Frank Lampard in midfield.

But the Chelsea coach scoffed at suggestions he was taking the game lightly ahead of their crunch showdown with league leaders Manchester United on Sunday.

Mourinho’s side need just one point to qualify for the knockout stage as Group A winners and, in his view, the game with Bremen is more important than the trip to Old Trafford.

He added: “This game is more important than Manchester United. We will play the best we can and try to get the best result.

“The position in the group is magnificent and we only need one point to qualify but that does not affect the way we approach the match.

“Barcelona is a great team and one of the favourites for the competition while Bremen is the outsider.

“Bremen don’t have the pressure to win the competition the way we, Barcelona, Inter or AC Milan have. I can tell you that I want to win.

“Manchester United is Sunday and the result in Champions league is no relation to that game and we are very calm and playing very well.

“For United we will have Carvalho and Lampard back. It’s a different team and a different game but Manchester United is not special.

“What I feel in relation to that game is that we are in second place and there is a long way to go.

“We do not want to be second in the league. We go there to leave again in first place in the table.”

Meanwhile, Arjen Robben has scoffed at suggestions he is unhappy at Stamford Bridge.

Robben’s future at the club was the centre of fresh speculation last weekend even though he returned to the starting line-up for the victory over West Ham.

The Dutchman was also tipped for a summer move to Real Madrid but remains a vital part of Mourinho’s squad.

The Holland international will have to settle for a place on the bench against Bremen but insists he remains happy.

Robben said: “I’m enjoying myself here and that’s what matters. Talk of moving in the summer was all rumour and I’m fully committed to Chelsea.”