LONDON — A superb Diego Costa strike stretched Chelsea's winning run to nine matches, equaling its streak from 2007, after it overcame West Brom 1-0 Sunday in the Premier League.
Costa's 12th goal of the season sees the Blues maintain their three-point advantage over Arsenal which briefly went top on goal difference after beating Stoke 3-1 Saturday.
The Gunners' north London rivals Spurs lost ground after going down to a 1-0 defeat at Manchester United. Spurs remain in fifth on 27 points, 10 adrift of Chelsea.
Later, Origi spared Liverpool blushes against West Ham with the equalizer for a 2-2 draw.
United, for whom Henrikh Mkhitaryan opened his account in the Premier League before going off on a stretcher in the second-half with what appeared a left ankle injury, is 13 points shy of the leader but only six off the Champions League spots.
United manager Jose Mourinho, who said he didn't think the injury to Mkhitaryan was serious and that the player risked missing just two weeks, hailed the three points haul as "magic".
West Brom made it difficult for Chelsea at Stamford Bridge until Costa seized on the ball 14 minutes from time, brushed off the attention of Gareth McAuley and rifled the ball past Ben Foster into the top far corner.
Chelsea manager Antonio Conte feted his players for winning nine in a row — scoring 23 and conceding just two goals — in a "very tough league".
The United and Spurs match was of a far better quality with the hosts going close through Paul Pogba, who hit the post and also forced Spurs' French goalkeeper Hugo Lloris into a superb save in the second-half.
The visitors could have gone home with a share of the points but for a woeful misdirected header from unmarked Kenyan midfield enforcer Victor Wanyama.
Liverpool took the lead but then had to come from behind in a game of thrills and spills as Juergen Klopp's men drew 2-2 with West Ham United.
Anfield's delight at the returning Adam Lallana's clever opener on five minutes turned to despair when it fell apart spectacularly before the break.
Liverpool keeper Loris Karius, at fault for Bournemouth's winner last week, let in a 20-meter free kick from Dimitri Payet despite getting a hand to the ball.
Defender Joel Matip then stumbled to allow a looping pass over his head for the on-running Michail Antonio to slot the ball beyond the stranded Karius in the 39th minute.
Third-placed Liverpool, though, did not have a trademark on mistakes and three minutes into the second half West Ham keeper Darren Randolph flapped at a cross from Sadio Mane, leaving Divock Origi a simple job to bag his fourth goal in as many games.
In a match involving two struggling teams, Southampton ended a bad week with a much-needed win, beating Middlesbrough 1-0.
Record signing Sofiane Boufal secured the three points with a delightful effort from the edge of the area.
Victory — only Southampton's second in seven matches — moves Saints eight points clear of the relegation places while 'Boro remain mired in the battle for survival, just three points better off than third from bottom West Ham.
