The win moves the Gunners a point ahead of Manchester United but crucially Mikel Arteta's side have three games in hand on their rivals for the final Champions League slot.
Arsenal have now won their last five games and a run of nine wins from their last eleven encounters in the Premier League has transformed their season after a poor start to the campaign.
Kai Havertz scored an 89th-minute winner to give Chelsea a 1-0 victory over Newcastle United in their first home match since Britain's government sanctioned Russian owner Roman Abramovich with an asset freeze.
The win left the Blues in third place in the table, 10 points behind leaders Manchester City who play tomorrow, while Newcastle are 14th, nine points clear of the relegation zone.
West Ham beat Aston Villa 2-1.
Watford beat Southampton to move up to 18th, just behind Everton on goal difference.... Southampton are tenth.
Everton lost 1-0 to Wolverhampton Wanderers to stay 17th.
Leeds scored in stoppage time to beat fellow strugglers Norwich City 2-1.