Makeshift striker Mikel Merino secured a first-half headed goal to help Arsenal secure a 1-0 win over Chelsea in English Premier League action Sunday.
Merino, who has been standing in for injured strikers Kai Havertz and Gabriel Jesus headed home from the near post on 20 minutes to give the Gunners a deserved lead after a solid start that had seen them dominate possession.
He was also denied by Chelsea keeper Robert Sanchez later on.
Sanchez who has been under fire this season after a series of high profile errors also saved from Leandro Trossard to keep his side in the game.
Chelsea improved as the match wore on but with their main man Cole Palmer missing together with striker Nicholas Jackson, they lacked the cutting edge to open up a determined Arsenal who has not won any of their last three league matches.
The win boosted the Gunners to 58 points, 12 behind leaders Liverpool with 9 matches left to play.
Chelsea remain fourth on 49 points. It also stretches their lead over third placed Nottingham Forest to four points.
Elsewhere, Rodrigo Muniz and Ryan Sessegnon were on the scoresheet as Fulham beat Tottenham Hotspur 2-0 at Craven Cottage.
After a first half that took forever to get going, Fulham, who knew they could be within four points off the top four with a win, upped their game to score two late goals.
They are on 45 points, four behind Chelsea who are fourth on the standings.