Jesse Lingard took his goal tally to eight in nine appearances since joining West Ham on loan from Manchester United as he netted twice in a 3-2 victory over Leicester in the Premier League.
The win in Sunday's clash allowed West Ham to dislodge Chelsea and move back into fourth place in the Premier League as they pursue Champions League qualification for the first time.
Earlier in the English top-flight, Allan Saint-Maximin came off the bench and delivered his own brand of magic to inspire Newcastle United to a vital 2-1 victory at Burnley that lifts them six points clear of the relegation zone.
David Moyes' West Ham were worth the points in the crucial battle at the London Stadium, holding off a late Leicester fightback to move to within a point of the third-placed Foxes.
Leicester's cause was not helped by a breach of COVID-19 rules by some of their players.
"Those involved have apologised for their poor judgement," Leicester said. "Our response to the matter will be concluded internally."
James Maddison, Hamza Choudhury and Ayoze Perez were all left out for what could potentially end up being a pivotal clash for the European aspirations of both teams.
A moment of quality from the in-form Lingard, in front of England boss Gareth Southgate, put West Ham ahead in the 29th minute.
Right back Vladimir Coufal cut the ball back to Lingard, who sent a precise volley past goalkeeper Kasper Schmeichel from the edge of the area.
Lingard struck again in the 44th when the Leicester defence was caught out by a long ball from Issa Diop.
Jarrod Bowen stayed just onside as he raced toward goal and, as Schmeichel came out, the winger squared for Lingard to tap into an empty net.
Bowen himself put the hosts 3-0 up just three minutes into the second half but familiar West Ham jitters set in when Arthur Masuaku lost possession and Kelechi Iheanacho lashed home.
Iheanacho also grabbed a second when he prodded in Marc Albrighton's cross at the start of six minutes of stoppage time.
At Burnley, as Newcastle trailed to Matej Vydra's first-half goal, they looked uninspired before Steve Bruce brought on Saint-Maximin and Callum Wilson in the 57th minute.
Within two minutes of his introduction, Frenchman Saint-Maximin ran into the penalty area, drawing three defenders before pulling the ball back for Jacob Murphy to fire in an equaliser.
Five minutes later, Saint-Maximin then scored a sensational individual goal, racing from the halfway line before finding the bottom corner.
Victory ended a seven-game winless run for Bruce's side, and the second-half display offered a road map out of trouble.