West Ham produced a resolute defensive performance until, in the 83rd minute, Leandro Trossard fired through a crowd of bodies and beyond Mads Hermansen, after strong work from Martin Odegaard. 

The Hammers, who had earlier seen Mateus Fernandes pass up a glaring chance, then saw Callum Wilson strike deep into stoppage time, only for referee Chris Kavanagh to rule Pablo had fouled David Raya following a VAR review.

Arsenal had started the first half strongly and was unfortunate not to go ahead in the ninth minute. Trossard's effort was pushed onto the crossbar by Hermansen, and he got another chance in the ensuing scramble, only for his second header to also hit the woodwork.

An injury to Ben White knocked Arsenal's rhythm, as Mikel Arteta temporarily moved Declan Rice to right-back. West Ham almost took advantage on the stroke of half-time, but Raya kept Valentin Castellanos' diving header out at full stretch.

Time appeared to stand still when the Hammers carved out an enormous chance, with Fernandes placing his shot from six yards out in the only place that Raya could stop it. 

The Gunners made that reprieve count when Odegaard offloaded for Trossard to finish, but there was another twist to come.

Wilson's drive crossed the line when a West Ham corner was only half cleared, but after a review, referee Chris Kavanagh ruled Pablo had impeded Raya, sparking wild celebrations among the visiting players and supporters.

Arsenal is now two wins from the title, while West Ham could find itself four points from safety with two games to play, if 17th-placed Tottenham beat Leeds United on Tuesday.