Patrice Evra has warned his Manchester United team-mates that they have no chance of beating Chelsea on Sunday if they defend as poorly as they have on occasions this season.

United have been written off in some quarters before their visit to Stamford Bridge, but while Evra believes that is all the motivation they need, the France defender says the champions must keep a clean sheet if they are to have any hope of defeating the team he thinks will be their main challengers for the Barclays Premier League title.

The fragility that has been evident against Manchester City, Sunderland, Liverpool and others this season reared its head again on Tuesday. United were forced to come from 3-1 down against CSKA Moscow at Old Trafford to secure the 3-3 draw that guaranteed their progress to the Champions League knockout rounds and Evra called for a marked improvement against Carlo Ancelotti’s team.

“Sometimes we seem to make life complicated for ourselves,” he said. “We need to make sure we don’t concede three goals on Sunday because then it won’t be easy to come back. We did it against City and against Moscow, but it is not the best way of doing things against Chelsea.

“If you concede three goals at home, you cannot say it has been a good performance from the defenders, but we did not concede a goal against Blackburn [on Saturday] and now we need to keep a clean sheet against Chelsea if we want to win the game. All the defenders need to focus because that will be the key to winning the game.

“We have enough quality to keep a clean sheet but we need to be strong. Chelsea are our most dangerous opponents for the title. I like it when people say we are not the favourites, though. When the game starts it’s 50-50 but people think we are going there to lose, so that’s good motivation for us.”

Evra has been embroiled in plenty of controversy against Chelsea. He was banned for four matches after a post-match confrontation with Sam Bethell, a groundsman, in the wake of United’s 2-1 defeat at Stamford Bridge in April last year and involved in a skirmish with Michael Ballack during the Community Shield at Wembley in August, when United accused the Chelsea midfield player of elbowing their defender.

Evra hopes that the match passes without incident, but his main concern is ensuring that Chelsea do not pull farther ahead in the title race. “Whenever I play against Chelsea something bad always happens,” Evra said. “There was trouble after one game [with Bethell] and then this season there was the incident with Ballack.

“I have to make sure this time that nothing happens. It is the right time to win there. We are two points behind them so we have to make sure we don’t lose, because it would be five and then it would be difficult.”