Chelsea coasted to a 2-0 win over West Bromwich Albion, who were reduced to 10 men for more than an hour, to maintain their unbeaten start to the season at Stamford Bridge.
Goals from Diego Costa, who has now scored 11 times in his 10 Premier League appearances, and Eden Hazard, put Chelsea in control even before West Brom defender Claudio Yacob was red-carded in the 28th minute for a two-footed lunge on Costa.
Later, Manchester United, who have struggled since Louis van Gaal took over, won 2-1 at Arsenal to climb to fourth with their first away win under the Dutch coach.
Arsenal, who have not finished outside the top four since 1996, slipped to eighth on 17 points — their lowest tally after 12 matches for 32 years.
Champions Manchester City stayed in touch at the top when they came from behind to beat Swansea City 2-1 at the Etihad Stadium with Stevan Jovetic and Yaya Toure finding the target.
Chelsea have 32 points from 12 games, followed by Southampton on 25 from 11 and Manchester City on 24 points from 12 games.
West Ham United, who started the day in fourth place on 19 points, slipped back after losing 2-1 at Everton.
Newcastle United continued their revival with a sixth successive victory and moved up to fourth with a 1-0 win over Queens Park Rangers – at least until Arsenal play Manchester United in the day’s late game at the Emirates Stadium.
In the day’s other games, Leicester City failed to score for the fifth successive league match in a 0-0 draw with Sunderland.
Burnley won away for the first time and climbed off the bottom of the table, beating Stoke City 2-1 with Danny Ings scoring twice in two minutes early in the match.