Carlo Ancelotti accepts Wayne Rooney's injury could give Chelsea an advantage in Saturday's huge Premier League clash at Old Trafford.
Rooney is certain to miss the game after suffering ankle ligament damage in United's 2-1 defeat at Bayern Munich in the Champions League on Tuesday night.
The England striker has scored 35 goals in all competitions, 26 of them in the Premier League, and his absence at Old Trafford has already given Chelsea a psychological boost.
Chelsea have smashed 12 goals in their last two games and with 30-goal Didier Drogba fit again, Ancelotti is hoping the Blues can make the most of Rooney's loss and go back to the top of the table.
"Everyone knows how Wayne Rooney is important for this team, he is a fantastic player," said Ancelotti. "He has had a fantastic season but his injury could be an advantage for us.
"Maybe sometimes a team can give more than 100 per cent when an important player is out. We have to pay attention to this.
"We need to show our play and do it for 90 minutes and stay concentrated. Man Utd are a very dangerous team and have a lot of players who can create difficulties for us.
"But we want to keep control of the game and to do this in Old Trafford is not easy. But we will try.
"Saturday is a very important game because we play a fantastic team who are top of the league now but I have always said the title will be decided at the end of the season.
"We will have a very good chance because our moment is good. We are fit and our confidence has improved after wins against Portsmouth and Aston Villa.
"We want to do our best. The destiny after the game will be with the winners, but nothing will be decided.
"If we are able to win, it is better for us. A draw is not a bad result because there are a lot of games and everyone of them is very important.
"But it is very difficult to win at Old Trafford. It is a fantastic stadium for me also, not only for Sir Alex. I won the Champions League there in 2003 and that is the best memory for me in my career."
Ancelotti does not believe United's players will be dispirited following their defeat in Munich.
He is also aware that Sir Alex Ferguson's squad has too much experience to have their minds on the return leg against Germans.
"I don't think that players of Manchester United will think about that defeat to Bayern," said Ancelotti.
"They have a lot of experience and will be able to look forward to the next game against us and then, after that, stay in focus for the return game against Bayern."
Ancelotti has been boosted by the return to fitness of Drogba, who missed two days' training with a minor groin problem. The Italian even went as far as confirming the striker will start on Saturday.
"Drogba was out but trained very good today," said Ancelotti. "We have trained very well this week. The team is fit.
"He is a very important player. He has scored 30 goals. The other strikers did a great job against Villa without him, but he is very important to us."
So far, Ancelotti has twice triumphed over Ferguson this season. Chelsea won the Community Shield 4-1 on penalties at Wembley and then beat United 1-0 at Stamford Bridge thanks to a goal from John Terry.
But Ancelotti insists that this time the pressure will be different because victory is so important for both sides.
Chelsea remain one point adrift of the Red Devils at the summit and so a United win would give Ferguson's team a massive advantage on the run-in.
"This game is more important than the previous two," added the Italian. "We are playing for the title so psychologically it is different."
