Chelsea secure their 11th successive Premier League win and equalled a club record as they beat Crystal Palace to move nine points clear at the top of the table.
Diego Costa scored his 13th goal of the season when he put the Blues ahead with their first attempt on target as he headed in from Cesar Azpilicueta’s floated cross.
Marcos Alonso nearly doubled the visitors’ lead as he hit the underside of the crossbar with a curling 25-yard free-kick.
Crystal Palace’s wasted their best chances of the game when Jason Puncheon headed wide and fired a free-kick narrowly over.
Chelsea has been unbeaten in 11 games so far, On 17 December 2015, Chelsea sacked Jose Mourinho for a second time, seven months after he had led them to the Premier League title, with the club 16th and only one point above the relegation zone.
A year later the Blues, who finished the 2015-16 season in 10th after Guus Hiddink steadied the club, are nine points clear as they chase a fifth Premier League title.
And in the four previous seasons they have topped the Premier League at Christmas – 2004-05, 2005-06, 2009-10 and 2014-15 – they have gone on to win the title.
Only several fine saves from Palace goalkeeper Wayne Hennessey denied Chelsea a wider margin of victory, the Welshman doing well to deny N’Golo Konte and Alonso, who later struck the woodwork.