Centre-backs Rob Holding and Gabriel Magalhaes scored in either half as Arsenal maintained their two-point lead over fifth-placed Tottenham Hotspur with a 2-1 win at West Ham United.
Arsenal went ahead on 38 minutes when Rob Holding, only in the team because of an injury to Ben White, headed home Bukayo Saka's corner for his first Premier League goal.
West Ham reacted well, though, with Declan Rice's header expertly pushed away by Aaron Ramsdale before Jarrod Bowen equalised with a smart 45th-minute finish.
But Arsenal scored the winner nine minutes after the break when the unmarked Gabriel met Gabriel Martinelli's delivery at the back post with a diving header beyond Lukasz Fabianski.
The Gunners move back up to fourth with 63 points after a perfect response to Spurs' 3-1 win over Leicester City earlier in the day.
A third loss in four matches leaves West Ham in seventh, on 52 points, three behind sixth-placed Manchester United.
West Ham: 8 May v Norwich (A)
Arsenal: 8 May v Leeds (H)
Referee: Mike Dean. Assistants: Ian Hussin, Darren Cann. Fourth official: Simon Hooper. VAR: Darren England. Assistant VAR: Matthew Wilkes.