Arsenal moved within seven points of Premier League leaders Liverpool as Jurrien Timber and William Saliba scored from corners to secure a 2-0 win over Manchester United.
Liverpool's 3-3 draw with Newcastle opened the door for Arsenal to close the gap and, after a frustrating first half against Ruben Amorim's well-drilled side, their set-piece prowess proved decisive.
In the absence of the injured Gabriel Magalhaes, it was Timber who made the breakthrough after half-time when he flicked home a wicked Declan Rice delivery at the near-post for his first Arsenal goal.
Saliba doubled their lead when Saka directed a delivery from the opposite side towards the back post, where Thomas Partey headed the ball across goal and it bounced in off his team-mate's backside.
Saliba's second took Arsenal's tally of set-piece goals to seven this season and they could have had more, with a succession of deliveries causing chaos in the Manchester United box and Mikel Merino heading narrowly wide when unmarked from another Saka centre.
Arsenal were indebted to David Raya for his excellent, one-handed save from Matthijs de Ligt before Saliba's goal. The Gunners goalkeeper later made a sharp stop from substitute Antony following a clever Manchester United free-kick routine to avoid a nervy finale.
Amorim, who made six changes to the side that beat Everton, had successfully nullified the Gunners in the first half but they could not withstand the hosts' pressure after the break as Arsenal boosted capitalised on Liverpool's dropped points at St James' Park to boost their title hopes.
Story of the match in stats
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