Chelsea stretched their lead at the top of the Premier League to 11 points with a 3-1 victory over a resolute Swansea City side at Stamford Bridge.
Antonio Conte's team looked in danger of a third draw in four league games when Fernando Llorente cancelled out Cesc Fabregas's early goal but Pedro and Diego Costa secured victory, producing a clean sweep of goals by Spanish internationals.
Chelsea, beaten only once in 20 matches in all competitions, have 63 points from 26 matches, with Manchester City, who are not in action this weekend, on 52 from 25.
Tottenham Hotspur could trim the gap to 10 points if they beat Stoke City at home on Sunday.
It was not the most convincing of displays by Chelsea, and Swansea, who equalised just before halftime, had a good shout for a penalty turned down shortly before a mistake by their keeper, Lukasz Fabianski, allowed Pedro's shot to put the league leaders back in front in the 72nd minute.
Costa wrapped up the points with his 16th league goal of the season, volleying in from Eden Hazard's pass.
"We conceded at the end of the first half, after the time was finished, so in this case there was a bit of luck, but we showed great character in the second half," Conte said.
"We deserved a lot to win the game. Now it's important to continue in this way. To look at ourselves and to think to win, to continue with great focus and concentration."
Chelsea were given the lead in the 19th minute when Fabregas marked his 300th Premier League appearance with a fine finish from Pedro's cut-back.
Swansea, much improved under the management of former Chelsea assistant coach Paul Clement, frustrated their hosts for long periods, though, and equalised when Llorente headed in from Gylfi Sigurdsson's quickly taken free kick.
Clement felt his side had been denied a clear penalty when Cesar Azpilicueta appeared to handle in the area.
"It's a clear handball," he said. "That gives you a chance to go 2-1 up with a penalty but three minutes later you're 2-1 down after a soft goal.
"Based on chances they deserved to win, but that was a big moment that didn't go our way."