Tottenham's downward spiral continued as West Ham moved into fourth in the Premier League with a 2-1 win against troubled Spurs on Sunday.
Jose Mourinho's side slumped to a fifth defeat in their last six league games as they paid the price for sloppy defence at the London Stadium.
Michail Antonio put West Ham in front early in the first half and Jesse Lingard doubled the hosts' advantage after the break.
Lucas Moura reduced the deficit with his first league goal since September, but Spurs were unable to salvage a point.
West Ham climbed two points above Chelsea into the Champions League spots as their unexpected European challenge gathered pace with a seventh win in their last nine league matches.
It was a first triumph for West Ham boss David Moyes in 16 meetings with Mourinho.
And while Moyes has sparked a remarkable revival at West Ham, who were in a relegation battle when he arrived last season, Mourinho's Tottenham are in the middle of a woeful campaign.
They are languishing in ninth and trail West Ham by nine points, albeit with a game in hand.
Tottenham have already lost eight league games this season – the second-worst return of Mourinho's career after losing nine with Chelsea in 2015-16.
Mourinho will have to turn the tide quickly to save his job after Tottenham's latest flop.
Tottenham had conceded nine goals in their last three games in all competitions, underlining the defensive flaws that have plagued them since they squandered a three-goal lead in the closing minutes of their 3-3 draw with West Ham in October.
Tottenham conceded a goal early in the first half with fit-again striker Michail Antonio converting a loose ball from close range after his initial glancing effort was kept out by goalkeeper Hugo Lloris in the fifth minute.
Mourinho threw Gareth Bale on at half-time but within two minutes of the restart they were 2-0 down.
Some shoddy defending saw Lingard surge through on goal and he fired into the bottom corner.
Spurs had a mountain to climb but they started the comeback midway through the second half when Moura headed in Bale's corner for his first Premier League goal since September.
Then the onslaught in the final 20 minutes started and it was only poor finishing that stopped them taking at least a point.
Moura blazed over from the edge of the area, Kane fizzed a low effort inches wide of Fabianski's post.
Spurs hit the woodwork twice in the final 15 minutes as they searched for a leveller.
Bale fizzed an effort that clipped the top of the crossbar from 18 yards and then, deep into injury time, Son Heung-min's deflected effort looped into the post, confirming that it was to be West Ham's day.
