Substitute Alexandre Lacazette scored the only goal as Arsenal beat West Ham United 1-0 at the Emirates on Saturday afternoon in a vital victory that boosts their European hopes.

In a game filled with plenty of chances it was the Gunners who took one, when Lacazette turned home Mesut Ozil's header with the goal given following a lengthy VAR check.

Despite a flat performance that left many supporters frustrated, the win keeps Arsenal's European hopes on track.

Mikel Arteta made six changes from the side that knocked Portsmouth out of the FA Cup on Monday night, with Bernd Leno, Granit Xhaka, Dani Ceballos, Nicolas Pepe, Mesut Ozil and Pierre-Emerick Aubameyang coming into the starting XI.

Emi Martinez, Matteo Guendouzi, Reiss Nelson, Joe Willock and Gabriel Martinelli dropped to the bench, while Lucas Torreira missed out after fracturing his ankle at Fratton Park.

Shkodran Mustafi was also sidelined with a thigh strain, meaning Pablo Mari kept his place to make his Premier League debut after joining on loan from Flamengo in January.

The hosts nearly made the worst possible start as Jarrod Bowen's low effort was tipped onto the post by Leno inside two minutes after Granit Xhaka had given the ball away, and the Hammers continued to look dangerous when Michail Antonio broke clear before getting his pass to Sebastian Haller all wrong with the Frenchman in place for a tap in.

Arsenal's first chance came with 13 minutes gone as Ozil saw his goal-bound shot well blocked by Aaron Cresswell, but West Ham kept causing problems as Leno was called into action to smother as Haller burst into the area.

The chances continued to come in a lively start to the game as the Gunners came close when Sokratis headed Aubameyang's cross onto the bar with 22 minutes played.

The game then settled down as both sides struggled to create any clear cut chances before the break, with the teams going into half-time level.

Arsenal saw all of the ball after the restart and had a good chance on 52 minutes when Saka drifted inside and slipped Nketiah through, but former Gunner Lukasz Fabianski was out quickly to make the save.

The visitors continued to have the better opportunities though, and Arteta's men would have been behind had it not been for Leno's superb reaction save to deny Antonio's close-range header.

The opening goal did finally come on 78 minutes, and it was the home side who got it as one of Arteta's substitutions paid off.

A deflected shot from Aubameyang bounced over the West Ham defence and into the path of Ozil, whose deft header was turned home by Lacazette on the edge of the six-yard box.

The offside flag went up on the far side to initially rule the goal out, but after a lengthy VAR check Ozil was ruled to be inches onside and the decision was overturned to put Arsenal ahead.

The Gunners then had Leno to thank again as he kept them in front, clawing away a shot at the near post from Haller.

Despite late pressure from West Ham, the hosts held on for a win to keep ambitions of Europe alive.