Eddie Nketiah scored his first Premier League double as Arsenal got their top-four hopes back on track with an entertaining 4-2 victory over Chelsea.
Mikel Arteta's faith in Nketiah was rewarded as the 22-year-old ended a wait for a league goal that stretched back to April 2021 with the opener at Stamford Bridge on Wednesday.
Timo Werner scored in consecutive Premier League games for just the second time in his Chelsea career to restore parity, before Emile Smith Rowe put Arsenal back in front.
Cesar Azpilicueta got another equaliser for Chelsea, but he was at fault for Nketiah's second and a stoppage-time penalty from Bukayo Saka as Arsenal ended run of three straight defeats and went level on points with fourth-placed Tottenham.
2 - Eddie Nketiah is the first Arsenal player to score a brace against Chelsea in the Premier League since October 2011, when Robin van Persie netted a hat-trick. Repaid. pic.twitter.com/FSQD69UQmV— OptaJoe (@OptaJoe) April 20, 2022
Andreas Christensen's bungled back pass was pounced upon by Nketiah and the attacker slotted a cool finish past Edouard Mendy to give Arsenal the lead in the 13th minute.
Chelsea hit back four minutes later when Ruben Loftus-Cheek won possession high up the pitch and Werner unleashed a shot that deflected in off Granit Xhaka.
Arsenal narrowly avoided gifting Chelsea a chance to take the lead and transitioned into a rapid counter-attack that finished with Smith Rowe placing a curling shot into the bottom-right corner.
The Blues drew level before the break, though, with Mason Mount's excellent delivery steered home by Azpilicueta.
Christensen made way for Thiago Silva at half-time, but Arsenal were back in front 13 minutes after the restart. Azpilicueta gave the ball away and Nketiah made the most of a couple of fortunate ricochets to double his tally.
Azpilicueta then hauled Saka to ground in the box and the England winger fired the spot-kick home in the 92nd minute as Chelsea succumbed to a defeat that left them in danger of being dragged into an unexpected top-four battle.
What does it mean? Shoddy defending costs Chelsea
Chelsea have lost three straight home games in all competitions for the first time in almost 30 years, and some sloppy errors brought on their latest defeat.
They gifted Nketiah a pair of goals and were caught short when their high press was beaten ahead of Smith Rowe's strike.
The Gunners were by no means in good form at the back, but some crucial blocks from Gabriel helped them secure a huge three points.
Marcos Alonso struggled to cope with Saka's dribbling ability as he proved extremely dangerous when Arsenal counter-attacked. He capped an all-action display with a deserved goal at the death.
Thomas Tuchel handed Romelu Lukaku his first start in over a month, but the Belgian failed to impress. His 22 touches were the fewest of any Chelsea starter and he missed the target with his only attempt on goal.
Arsenal entertain Manchester United in a game that could be key to their top-four hopes on Saturday, while Chelsea have another London derby against West Ham the following day.