Chelsea defender Branislav Ivanovic has urged his teammates to remain focused for the whole 90 minutes against Manchester United on Sunday.

The European champions will host the Red Devils in the Premier League, aiming to extend their four-point lead over Sir Alex Ferguson's side at the top of the table.

"This style is the change of the team and we defend like a team, and the same in attack," he is quoted as saying on Chelsea's official website.

"This has worked to our advantage and we must carry on but we have to stay compact in this kind of game, and make things easier for our teammates.

"'This is one of the crucial games for us this season, against Man United, with two difficult games before it. We have time to recover [after midweek's Champions League clash with Shakhtar Donetsk] and do well. We know it's difficult to play against United and we have to be focused for the whole 90 minutes if we want to win it."

Chelsea have picked up 22 points from eight matches so far and have yet to lose in the Premier League.