Manchester City midfield pair Ilkay Gundogan and Fernandino were on target as Pep Guardiola's Premier League superiority over West Ham continued.
City have now won 10 out of 11 top-flight meetings with the Hammers under the Spaniard.
In a game played in a snow-storm before half-time, skipper Gundogan provided the decisive moment after 33 minutes when he turned home a deflected Riyad Mahrez effort at the far-post.
It was the Germany midfielder's third goal of the season - and his second in four league games - and was followed up in the final minute by Fernandinho, who had only been introduced three minutes earlier to tie the game up.
The veteran Brazilian had not scored a Premier League goal since October 2018 but found the target from the edge of the box.
Manuel Lanzini pulled one back with the final kick of the game, which cost Ederson his 100th clean sheet in all competitions but did nothing to prevent City moving back into second spot, six points clear of the Hammers.
The Londoners remain fourth despite suffering successive Premier League defeats for the first time since April.
Jamie Vardy scored twice as Leicester beat Watford in a hugely entertaining match to ruin Claudio Ranieri's return to the King Power Stadium.
Ranieri was in the opponents' dugout for the first time since guiding the Foxes to the 2015-16 Premier League title and received a great reception from the home fans.
But in a chaotic and thrilling game played in blizzard conditions, his current side played a big part in their own downfall.
There looked to be no danger when Jonny Evans launched a free-kick forward, but William Ekong ducked under the ball and that allowed James Maddison to fire the 16th-minute opener past Daniel Bachmann.
Watford were gifted a chance to equalise in the 30th minute when Wilfred Ndidi clumsily chopped down Emmanuel Dennis and Joshua King fired his penalty into the top corner.
But the hosts retook the lead four minutes later with an unmarked Vardy glancing a header in from Maddison's corner. The pair combined again just before half-time with Vardy lifting a fine finish for his second and Leicester's third goal.
Dennis then dispossessed Timothy Castagne and calmly finished to make it 3-2 in the 61st minute, but the hosts quickly restored their two-goal advantage when Harvey Barnes set up Ademola Lookman for a close-range tap-in.
The victory takes Leicester up from 13th into ninth, while Watford remain 16th, four points above the relegation zone.
