Pep Guardiola's men are now 13 points clear thanks to a 20-game winning run in all competitions that has seen them close in on an unprecedented quadruple of trophies.

For the first time in recent weeks, City showed signs of fatigue, though, and needed the centre-back pairing that has been a huge part of their success defensively this season to also make their mark at other end.

"After 10 or 15 minutes today we realised we were not going to paint anything beautiful," said Guardiola. "When you play a lot of games - in the league and then the Champions League - this is normal. We were lucky to get all three points."

Kevin De Bruyne made just his second start since returning from a hamstring injury and the Belgian's teasing cross was powered by home by Dias for his first City goal since joining from Benfica in September.

City had kept eight clean sheets in their previous 10 league games, but West Ham showed why they are fourth and pushing to edge out the likes of Liverpool, Chelsea, Tottenham and Arsenal to qualify for next season's Champions League.

Michail Antonio had already threatened an equaliser by hitting the post before he did level by tapping home Jesse Lingard's mishit shot just before half-time.

Stones was harshly dropped for a 2-0 Champions League win at Borussia Monchengladbach in midweek after revitalising his career this season, and the England defender smashed home Riyad Mahrez's pass to restore City's lead on 68 minutes.

West Ham could still have snatched a point deep into stoppage time when Issa Diop headed a glorious chance wide.

"I'm really disappointed we didn't get a point," said West Ham boss David Moyes. "It was a terrific performance. We came here and tried to match a top side - and for long periods we did."

Blunder costs Brighton

West Brom kept their hopes of avoiding the drop alive with just a second win in 13 games under Sam Allardyce in a game overshadowed by a surreal moment of refereeing by Lee Mason that cost Brighton an equaliser.

Kyle Bartley's early header gave West Brom the lead before Pascal Gross hit the bar from the penalty spot for the visitors.

Brighton did have the ball in the end when Lewis Dunk's quickly taken free-kick, after Mason had whistled for it to be taken, caught Sam Johnstone napping.

Mason initially did not award the goal before reversing his decision. However, after reviewing the incident on VAR, the goal was ruled out as the referee changed his mind for a second time.

"Lewis Dunk takes a quick free-kick and bends the ball into the net but after consulting the VAR, referee Lee Mason has overturned the goal because the whistle had been blown a second time before the ball had crossed the line," the Premier League said in a statement to justify the decision.

Victory for the Baggies hauls Allardyce's men to within eight points of safety, while Brighton remain just four points clear of the drop zone in 16th.

kca/mw