Bukayo Saka banished his Euro 2020 final penalty shoot-out ghosts by converting a spot-kick as Arsenal toppled Chelsea 4-2 to reignite their bid for a top-four Premier League finish.
The England forward slotted home his first-ever penalty for Arsenal to seal the Gunners' vital win over the Blues, that drew Mikel Arteta's men level with fourth-placed Tottenham in the table.
Saka missed the last penalty in England's 3-2 shoot-out defeat to Italy in the Euro 2020 final at Wembley last July.
The 20-year-old won the late spot-kick at Stamford Bridge by drawing a foul from Cesar Azpilicueta, and quickly insisted on taking the penalty himself.
Saka dismissed any nerves by side-footing home to boot, to put the seal on a crucial win for the Gunners.
Eddie Nketiah had twice seized upon slipshod defending to drive Arsenal into a 3-2 lead before Saka's strike.
Nketiah capitalised on Andreas Christensen's woefully under-hit back-pass for his first Arsenal goal in 367 days, to open the scoring in west London.
The 22-year-old forward later settled a scrappy but engrossing contest when three attempted Chelsea clearances landed the ball straight into his path and through on goal.
Timo Werner's deflected effort had Chelsea level quickly after Nketiah's first goal, with captain Azpilicueta then cancelling out a fine finish from Emile Smith Rowe before half-time.
The fatigued and off-kilter Blues were made to pay for a string of errors however, with £98m striker Romelu Lukaku again failing to fire.
Toni Rudiger's absence with a minor groin problem destabilised Chelsea's defence, and Christensen endured a night to forget.
The Denmark international was withdrawn at half-time in a below-par showing, but not even the peerless Thiago Silva could sharpen up the hosts.
Arsenal took full advantage of Chelsea's malaise to notch just their second win in six league matches, breaking a wretched run of results to move below Spurs on goal difference, leaving the race to finish fourth wide open.
Lukaku's sole meaningful act of a quiet first half was to drag wide after being played in by Ruben Loftus-Cheek.
Chelsea had been under precious little pressure from the off, but constituted their own downfall with Christensen's horror-show attempted back-pass.
The defender majorly under-sold his attempted pass to Edouard Mendy, instead gifting Nketiah a stroll in on goal.
Nketiah needed no second invitation, and duly cantered in before providing a crisp finish.
Chelsea were level just four minutes later however, as Werner's 20-yard strike took a significant deflection off Granit Xhaka to beat Aaron Ramsdale at his near post.
Smith Rowe quickly had Arsenal 2-1 ahead however, with a sharp sidefooted finish after Saka had combined well with Martin Odegaard, who provided the assist.
The Blues needed just five minutes this time to level, with Azpilicueta sneaking in to provide a poacher's finish to Mason Mount's teasing cross.
Smith Rowe had the last word in the half as Arsenal attacked again, but this time could only whip his effort wide of the post.
Silva replaced Christensen at the break, with the 37-year-old clearly drafted in to sure up the Blues' backline.
Not even the peerless Brazilian could solve Chelsea's defensive shortcomings however, as Arsenal took the lead again.
Silva won the ball at full stretch only for Malang Sarr to bungle the attempted clearance, allowing Nketiah to pounce for his second of the night.
The ball fell kindly for Nketiah, but Chelsea again set themselves up to fail with woeful defending.
Lukaku was replaced by Kai Havertz moments after the goal, with a large swathe of the Blues support booing the Belgium striker.
Chelsea could find no route back into the contest, and at the death the Blues conceded a spot-kick.
Saka stepped up seemingly well aware of his attempt to erase any lingering Euros memories, and he wrapped up a fine Arsenal result with a coolly converted effort.