A brace from Tomas Soucek helped West Ham come from behind to win 3-2 at Crystal Palace and move into the Premier League top four.
David Moyes watched his in-form side make a poor start to the London derby when Wilfried Zaha grabbed the opener after three minutes.
But it was largely one-way traffic afterwards, with Soucek hitting a first-half double to take his tally for the campaign to seven while Craig Dawson wrapped up the points with a fine header after the break.
The Hammers have now won their last six games in all competitions and are up to fourth which has put them in the mix for European football next term.
Visa issues ensured Palace new boy Jean-Philippe Mateta was not part of the squad, which meant Christian Benteke led the line for the hosts and he made an early impact in an action-packed start.
Roy Hodgson saw his side take the lead after only three minutes when Zaha netted his ninth goal of the season with a drilled effort from 20 yards.
It occurred after the Eagles attacker had played a smart one-two with Benteke on the edge of the area, but West Ham were not behind for long.
Pablo Fornals' cross looked to be going out of play, but Michail Antonio chased the lost cause and hooked the ball across goal for Soucek to head in his sixth of the campaign.
Just love him. #CRYWHU pic.twitter.com/GeKY3gWYQs — West Ham United (@WestHam) January 26, 2021
The Czech Republic international was now the outright top goalscorer for the Hammers in the Premier League this season but was not finished there.
Midway through the first half Soucek doubled his and the visitors' tally for the night when he controlled Aaron Cresswell's free-kick and steered the ball in from a tight angle.
VAR had to check for offside but the goal was given and Palace were fortunate not to be 3-1 down when Antonio raced clear and saw his effort hit the inside of a post before it bounced away to safety.
With the carrot of moving into the top four with a victory, West Ham looked to press home their momentum and the frame of the goal saved Hodgson's side again six minutes before the break when Cresswell's shot-cum-cross ricocheted off Antonio and onto the other post.
Frustration had started to get the better of the hosts prior to half-time, with Zaha and James McArthur exchanging words, but they almost got back on level terms two minutes into the second half.
Ebere Eze sent goalscorer Zaha through and yet Lukasz Fabianski made himself big to impressively deny the Ivory Coast ace a second goal.
Moyes' men should have put the game to bed close to the hour mark when Said Benrahma did well on the right and picked out Antonio. Vicente Guaita saved from close range, but it would not prove decisive.
With 65 minutes played, West Ham finally made their dominance count when Dawson headed in Jarrod Bowen's inswinging corner to make it 3-1.
Michy Batshuayi had been ready to come on for Palace prior to the set-piece, but by the time he entered the fray their task had got a whole lot harder.
The Belgian was able to pull a goal back deep into stoppage time – his first for the Eagles since he returned on loan from Chelsea – but it failed to stop West Ham moving above Liverpool and into fourth.
