The Ghanaian forward helped his to secure a 1-0 victory over title contenders Tottenham Hotspur at the London stadium on Friday night.
The Black Stars deputy captain provided an assist for Lanzini to score the only goal in the game on the night on the 65th minute.
Lanzini popped up to fire home in the second half, leaving Spurs four points behind Chelsea after extra game.
Mauricio Pochettino’s side knew a win at the home of their arch rivals would increase the pressure on the Blues, who face Middlesbrough on Monday night but at the end dropped all three points in the crucial game.
The likes of Harry Kane and Dele Alli always seemed to be just slightly off the pace, with the Hammers biding their time and looking dangerous on a number of counter attacks.
But it was Lanzini who grabbed the only goal of the game, a just reward for the Argentine after giving Jan Vertonghen a torrid time.
Ayew did not finish the entire duration after being substituted for Snodgrass in the 83rd minute.