Chelsea took sole possession of first place in the Premier League table after they beat Newcastle United 2-0 on Saturday and Manchester City drew 1-1 at Everton.
Chelsea began the day dead-level with City, but with the defending champions dropping points for only the second time in 10 matches, Jose Mourinho’s side moved two points clear.
Newcastle had beaten Chelsea 2-1 in the reverse fixture and despite still being without a manager following Alan Pardew’s departure, they threatened to pull off a repeat in the first half at Stamford Bridge.
Petr Cech was deputising in goal for Chelsea due to a finger injury to Thibaut Courtois and he had to save from Remy Cabella and Yoan Gouffran, while Moussa Sissoko slammed a shot against the post.
Chelsea lost Cesar Azpilicueta to an apparent groin injury in the 37th minute, but they went ahead six minutes later when Oscar tapped in Branislav Ivanovic’s cross after Willian took a quick corner.
Mourinho’s team were far from their best, but they added a delightfully constructed second goal just before the hour, with Diego Costa gathering a clever back-heel from Oscar and drilling in his 15th goal of the campaign.
“You always want to play well, but that’s not always possible,” said Chelsea assistant coach Steve Holland.
“It is important that when you don’t play as well as you’d like to, you still get the result.”
At Goodison Park, Everton enjoyed the best of the first half against City, with Seamus Coleman hitting the bar.
City went ahead in the 74th minute when Fernandinho helped a deflected shot from David Silva over the line with his head, but Steven Naismith equalised four minutes later, glancing home a free-kick from Leighton Baines.
“In the first half we had clear chances,” said City manager Manuel Pellegrini, who welcomed Sergio Aguero back from injury.
“In the second half Everton improved and had a chance to draw and did so. If you said at the beginning you are going to draw at Everton away, maybe it is not so bad.”