Arsenal breathed life back into their Premier League title charge as Danny Welbeck's 95th-minute winner sealed a 2-1 victory over 10-man Leicester on Sunday.
Welbeck struck late on to break Leicester's resolve after the league leaders looked to have survived 40 minutes with a man down, following Danny Simpson's dismissal for a second bookable offence.
Jamie Vardy's first-half penalty seemed to have set the Foxes on their way to victory until substitute Theo Walcott struck 10 minutes after coming off the bench to ignite a late Arsenal revival.
The inspired Kasper Schmeichel and Leicester's valiant defensive unit kept Arsenal at bay only for Welbeck, making his first appearance since April 2015, to strike deep into stoppage time.
The result moves Arsenal above north London rivals Tottenham into second spot and, crucially, to within two points of leaders Leicester.
Arsene Wenger made two changes to the Arsenal side fielded at Bournemouth, with Per Mertesacker replacing the injured Gabriel and Mathieu Flamini making way for Francis Coquelin, who made his first Premier League start since November, while Leicester were unchanged from the side that comprehensively beat Manchester City last weekend.
Arsenal made the brighter start as Alex Oxlade-Chamberlain was played in behind the Leicester defence, but Simpson was on hand to clear before the right-back forced Alexis Sanchez to head the resulting corner wide inside two minutes.
Oxlade-Chamberlain was involved again after as his chipped pass appeared to strike N'Golo Kante's arm, but referee Martin Atkinson was unmoved.
A cagey opening 10 minutes passed before the game sprung into life as both sides exchanged blows in search of an opener. First, Christian Fuchs played Shinji Okazaki through on goal, only for the offside flag to deny the striker.
Aaron Ramsey was then played into acres of space prompting Schmeichel to race off his line on 15 minutes to intervene, before Petr Cech produced a brilliant save to keep out Vardy's low header a minute later.
Olivier Giroud and Sanchez were then denied by Leicester captain Wes Morgan, who threw his body in the way of shots twice in the space of five minutes, before Giroud's 31st-minute header was ruled out for offside.
And the Foxes took advantage of their reprieve as Vardy ended a brisk counter by drawing Nacho Monreal into a rash challenge which left Atkinson with no choice but to award the spot-kick.
The England striker dusted himself down and rattled the ball home from 12 yards - his 19th Premier League goal of the season.
Arsenal were forced to replace Laurent Koscielny at half-time due to an injury, but that failed to prevent Arsenal from flying out of the traps when played resumed, with Ramsey dragging an early shot wide.
Monreal was lucky to avoid giving another penalty away as he brought Riyad Mahrez to ground in the area, but this time Atkinson waved the claims away.
The game then swung in Arsenal's favour as Simpson picked up two yellow cards in quick succession, the second for bringing Giroud to ground.
Mahrez was sacrificed as Leicester battened down the hatches, and Arsenal's pressure soon told as Walcott rifled home superbly after Giroud's fine knock-down in the area.
Arsenal continued to throw bodies forward against a tiring Leicester team, but Schmeichel proved impenetrable.
Welbeck was brought off the bench to make his first appearance of the season, having been sidelined for 10 months after undergoing knee surgery, and it proved to be a comeback to remember for the England international, as his deft flicked header saw the Gunners finally beat Schmeichel with the last kick of the game.
Arsenal: Cech (6), Bellerin (6), Mertesacker (6), Koscielny (5), Monreal (5), Coquelin (5), Ramsey (6), Oxlade-Chamberlin (6), Ozil (6), Alexis (7), Giroud (7).
Used subs: Chambers (7), Welbeck (8), Walcott (8)
Leicester: Schmeichel (9), Simpson (5), Morgan (7), Huth (7), Fuchs (6), Mahrez (6), Kante (9), Drinkwater (8), Albrighton (7), Okazaki (7), Vardy (8).
Used subs: King (5), Gray (6), Wasilewski (5).
Man of the Match: N'Golo Kante.