Chelsea manager Guus Hiddink gave the biggest hint yet that his side's title challenge is over after they suffered a 1-0 defeat at London rivals Tottenham.
Manchester United's earlier 2-0 defeat by Fulham meant a win at White Hart Lane would have seen Chelsea close to within a point of the league leaders.
But defeat leaves them four points adrift and having played a game more.
"These are the days you look back on and regret very much when you are in a title race," admitted Hiddink.
"We won't give up on the title, but today was an ideal opportunity to close the gap on Manchester United and we missed it.
"We cannot afford to drop two or three points in any game if we want to catch United, and today we lost - it's a huge blow. Let's be honest - if you don't win at moments like today you have to blame yourselves."
Luka Modric got the only goal of the match to condemn Chelsea to their first league defeat under Hiddink.
It was no more than Tottenham deserved from a fine display, though the hosts were thankful to two fine saves from keeper Heurelho Gomes - from Nicolas Anelka and John Terry - as they saw out the victory.
And Hiddink conceded: "I can't argue with the result - it was a fair reflection.
"We paid the price for some very sloppy defending at the start of the second half, when we were asleep for 10 minutes and let them in."
However, the Dutchman, who leaves the club to take charge of Russia for the next fortnight, urged his side to make the most of their push to win the Champions League and the FA Cup.
"We have two other roads to trophies and we must learn a big lesson from today if we want to challenge for those," he said.
Chelsea face Liverpool in the last eight of the Champions League and Arsenal in the semi-finals of the FA Cup.
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