Chelsea manager Andre Villas-Boas has admitted that his side could be out of the title race if they lose to Manchester City on Monday.
Chelsea are currently 10 points behind top-of-the-table City, and Villas-Boas believes that a loss would make that gap unassailable.
"We continue to challenge for the Premier League if we win or if we draw," said the 34-year old.
"But the Premiership becomes extremely difficult if we lose - because 13 points away would be something [worse] than what is already a big, big distance.
"There will be no quitting. It's not impossible to recover, but that's a reality. We all agree at the moment that Tottenham and Man United are the teams up there challenging."
Chelsea have already lost to Manchester United, Arsenal and Liverpool this season.