The Chelsea manager says all the teams in the Premier League title hunt will be feeling the pressure to go the rest of the season error-free.
One mistake could cost the title, says Chelsea's Ancelotti
The Premier League's top three teams are all in action this afternoon, playing on the same day for the first time since February 1.
With their trip to West Ham United the early kick off (3.45pm), leaders Manchester United could have an eight-point lead on second-placed Arsenal by the time the Gunners take on Blackburn Rovers at the Emirates Stadium in today's late game (8.30pm).
Chelsea, in third and nine points behind United at the start of the day, face a difficult trip away to Stoke City (6pm), but Carlo Ancelotti, their manager, believes his side can still have a say in the destination of the championship with the pressure now on.
"To make a mistake now is very dangerous," he said.
"Make a mistake here you can lose your possibility to win something.
"It's not just for us. Also Manchester United, also Arsenal. They cannot make a mistake either."
The champions have bounced back from a poor run of form at the end of last year with a strong sequence of results in March to put themselves back in contention to retain their title.
At one stage they had trailed United by 15 points, and Ancelotti added: "Three months ago, November or December, it would have felt like a dream to arrive in this situation now.
"I don't know what we will achieve in the end, but we have a possibility to fight."
With their destiny in their own hands, Sir Alex Ferguson's side are in the best position. But the Scotsman has injury worries ahead of today's trip to a resurgent West Ham.
Ferguson is undecided on whether to use Rio Ferdinand at Upton Park, as the defender is recovering from a calf injury that has kept him sidelined since February.
The England defender returned to training this week, but Ferguson conceded that West Ham and the midweek Champions League clash with Chelsea have probably come too soon for him.
"He has only been training two days and then just a light session today," Ferguson said yesterday.
"I have to decide whether we bring him in tomorrow or give him a day off and start him on Wednesday [against Chelsea] again. He is more likely to be fit for Fulham."
Ferguson does have Nemanja Vidic fit again, and the Serbian is likely to partner Chris Smalling in the heart of the defence in the expected absence of Ferdinand.
Meanwhile, Arsene Wenger has called for more consistency from his Arsenal side ahead of their home game with lowly Blackburn.
Wenger's team have dropped points in their last two league games, against Sunderland and West Bromwich Albion, which both ended in draws, and the Frenchman knows his side can afford to make no more mistakes on the title run-in if they are to be champions for the first time since 2003/04.
"Our target is to continue our unbeaten run and to win again because we haven't beaten Sunderland or West Brom," Wenger said.
"Of course, it's important to have the good basis of an unbeaten run, but what will make the difference is the three points."