Chelsea racked up a fourth consecutive English Premiership football League win without conceding a goal as they outclassed Southampton 2-0 with strikes from Eden Hazard and Diego Costa at St Mary's.
Everton beat West Ham 2-0 in the day's other game.
Hazard cut back and rifled a shot through Fraser Forster's legs after six minutes and Chelsea never surrendered their command.
Spain striker Costa doubled the lead 10 minutes after the break when he received a pass from Hazard and beat Forster with a swerving shot from 25 metres.
Chelsea, who moved back above Tottenham Hotspur into fourth spot just one point off the leaders, had the opportunities to increase their tally while Southampton's best chance fell to Charlie Austin who headed over the bar.
Romelu Lukaku's 50th league goal for Everton put them on the way to a deserved 2-0 victory over West Ham United, ending a run of four league games without a win.
It kept the Merseysiders sixth in the table, maintaining an unbeaten home record in the Premier League under manager Ronald Koeman, who replaced Roberto Martinez in the close season.
West Ham have now lost four of their five away games and could drop into the Premier League's bottom four after Stoke City's game with Swansea City tomorrow.
Manchester City are on top of the table with 23 points, Arsenal and Liverpool are behind them on goal difference.
Chelsea have 22 points, Spurs 20 and Everton 18.