The Blues won a highly-controversial game at Stamford Bridge last night, denting United's bid to deposing them as champions and keeping their own paper-thin hopes of retaining their crown alive.
But the 2-1 victory was too little, too late as far as manager Ancelotti was concerned as he claimed Champions League qualification was now the only realistic target for Chelsea.
Conceding defeat: Ancelotti believes that Chelsea won't be able to bridge the 12 point gap between themselves and Man United
'We are too far from Manchester United,' said Ancelotti, whose side are now fourth in the table, 12 points adrift of United with a game in hand.
'It's difficult for them to lose points in the next few games.
'We have to concentrate on ourselves and look not too far in the future.
'I cannot believe we are this far behind, but we have to be honest.
'This is where we are in the table, and United have played with more consistency than us.'
Consistency: Ancelotti believes it is Chelsea's lack of consistency that sees them so far off United
Winner: Frank Lampard celebrates scoring against Man United
Chelsea could close the gap to nine points if United lose at Liverpool on Sunday and they win at Blackpool the following evening.
And with a trip to Old Trafford to come and Sir Alex Ferguson's men also yet to visit Arsenal, there is still the tiniest glimmer of hope for the faltering champions.
Midfielder Frank Lampard, who netted the winner last night with a controversial penalty, said on Sky Sports: 'We just had to win the game, close the gap and send out a signal that we're still fighting.
'There's still a long way to go - Manchester United are still deservedly top of the league at the moment.'
Having written off Chelsea's title challenge, United boss Ferguson last night joked bitterly that they might get back into it if they continued to benefit from the kind of refereeing decisions that went their way in the second half.
It was debatable whether Chris Smalling had tripped Yury Zhirkov for the winning penalty or whether the Russian had stuck his own leg out to ensure contact was made with the defender.
But there was no doubt David Luiz - who had equalised with his first Chelsea goal - should have been shown a second yellow card for a cynical trip on Wayne Rooney two minutes before the spot-kick.
Ancelotti admitted Luiz may have been lucky to escape but refused to comment on referee Martin Atkinson's performance.
Screamer: David Luiz (right) celebrates scoring his first goal for Chelsea
He said: 'The referee took some decisions, but I don't want to judge them.'
Of the all-action display of ?25million January signing Luiz, Ancelotti added: 'He scored an important goal, the key to the game, and he's a very good player.'
Ancelotti also shrugged off another goalless outing from his other January capture, ?50million man Fernando Torres.
He said: 'Ask him, not me, if it will affect him but I don't think it will.'
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