Arsenal returned to the top of the Premier League table as Gabriel's close-range finish gave them victory away to Chelsea at Stamford Bridge.
Gabriel pounced to steer the ball over the line in the 63rd minute, after the hosts failed to deal with Bukayo Sako's corner from the right wing, to give the Gunners a deserved lead.
They had created the best chances when it was goalless but Gabriel Martinelli curled a shot over the crossbar and Gabriel Jesus failed to hit the target with a diving header when unmarked.
Chelsea, with ex-Arsenal captain Pierre-Emerick Aubameyang failing to make an impact against his former side, struggled to create clear-cut chances and are now without a win in four Premier League matches.
Arsenal lost top spot on Saturday when 10-man Manchester City beat Fulham 2-1 thanks to Erling Haaland's winning penalty in the fifth minute of injury time, but this win takes them two points clear of Pep Guardiola's side after 13 matches.
Source: BBC