Alexis Sanchez's answer to Craig Dawson's opening goal proved to be only a brief respite for Arsene Wenger, with Hal Robson-Kanu restoring the Baggies' lead before Dawson sealed it with a second.
PREMIER LEAGUE SCORES
|West Ham||2-3||Leicester City|
After West Brom had put paid to Arsenal in the lunchtime kick-off, Chelsea took another step towards the Premier League title by beating Stoke City thanks to Gary Cahill's late winner.
Jonathan Walters' penalty looked like it would be enough to earn a point for the Potters until Cahill converted from a corner with three minutes to play. Having taken the lead through a Willian free-kick, the Blues' latest win was once again founded on resilience and opportunism - qualities they are displaying week after week as they edge closer to reclaiming the championship.
At the other end of the table, Sunderland's situation looks fatal. Their 0-0 draw against Burnley, who are winless away from home, was the fourth game in a row in which they have failed to score and the Black Cats are now seven points adrift of safety.
It was also a bad day for Hull City, who have shown signs of life under Marco Silva but continue to run into extremely difficult fixtures that halt their momentum. They have lost four league games since Silva took over; away at Chelsea, Arsenal, Leicester City (after Craig Shakespeare had taken the reins) and now Everton.
Their 4-0 defeat was compounded by a narrow 1-0 win for Crystal Palace over Watford thanks to Troy Deeney's own goal, while Leicester City continue to look a team reborn and saw off West Ham away from home.
Sunday saw Manchester United pick up three points at Middlesbrough and vault up to fifth in the table, while Tottenham's win and City's draw keep Spurs in second.
PREMIER LEAGUE TABLE
Tottenham's win cut Chelsea's lead at the top of the Premier League. back to 10, while City drop further back. United and Arsenal are some way behind, though they have two games in hand over rivals Liverpool in the race for the Champions League
At the bottom, the picture is looking increasingly bleak for Sunderland and Middlesbrough. The latter will hope a new manager can inspire an unlikely escape in the final weeks of the season after Aitor Karanka departed.
AGUERO COMES UP BIG FOR CITY
After ever-steady James Milner converted a penalty for Liverpool in the second half of a wild, back-and-forth contest with Manchester City, it looked as though Pep Guardiola's men were going to have a miserable few weeks. After collapsing in the Champions League, City must travel to face Arsenal and Chelsea.
But Sergio Aguero once again came up big for Guardiola, knocking home an equaliser to make sure City had at least one point and a decent result to wipe the taste of the Champions League exit out of their mouths.
There's no doubt players like Aguero will need to keep their faith in Guardiola's system during a daunting pair of upcoming weeks. Aguero's goal made that much easier Sunday.
CONTE NO ONE-TRICK PONY
Nineteen wins, two draws and one defeat. That is Chelsea's astonishing Premier League record since they switched to a 3-4-3 formation and Antonio Conte, understandably, has rarely strayed from the winning formula.
At Stoke City on Saturday, though, he was forced to. The Blues' performance was tailing off into a 1-1 draw at the bet365 Stadium until the Italian rolled the dice, ditching the back three for a 4-2-3-1 and bringing on Cesc Fabregas for Victor Moses.
It worked. Chelsea finished the match on the front foot and capitalised when Erik Pieters inexplicably blocked a header from a corner harmlessly making its way to Lee Grant, allowing Gary Cahill to smash home the loose ball.
No manager has used fewer players than Conte this season but he has coaxed absolutely everything out of a core of 13. He was without one his best ones, Eden Hazard, for this match but has deployed Cesc Fabregas masterfully, benefiting from the production of one of the most efficient playmakers in the league while masking his tactical limitations.
ALSO OF NOTE...
Leicester's decision to put their Premier League survival in Craig Shakespeare's hands is looking increasingly like a masterstroke, with the interim manager recording a perfect four wins out of four in all competitions so far.
After the Foxes' latest win, a 3-2 triumph over West Ham, his start to life in the dugout is going into the history books. Shakespeare is the first manager in Premier League history to see his team score three goals or more in each of his first three games in charge.
Key to their fine form has been the revival of wingers Riyad Mahrez and Marc Albrighton; Mahrez has scored as many goals under Shakespeare as he did in his final 22 games under Claudio Ranieri, while Albrighton has had a hand in three goals in his last four appearances - as many as in his previous 27 games.
Leicester's win means Burnley are now the only team in the Premier League yet to win away from home, but the 0-0 stalemate at Sunderland was a better result for them than David Moyes' side.
Sunderland have now failed to score in a league-worst 13 matches this season and goalkeeper Jordan Pickford played more passes and had more touches than any other Black Cats player on the day.