Down to 10 men following Danny Simpson's 54th-minute dismissal, Leicester were clinging on at a tension-bound Emirates Stadium when Welbeck headed in a 95th-minute winner from Mesut Ozil's free-kick on his return after 10 months out with a serious knee injury.

The England striker's goal lifted Arsenal to within two points of Leicester and also gave hope to Tottenham Hotspur and Manchester City, five and six points off the pace respectively, ahead of their meeting at the Etihad Stadium later in the day.

Welbeck's goal, after fellow substitute Theo Walcott had cancelled out Jamie Vardy's first-half penalty, saw Arsene Wenger's men complete a league double over Leicester following their 5-2 win in September.

Claudio Ranieri's men now have two weeks to regain their strength before resuming their improbable title bid at home to Norwich City, while Arsenal must prepare for contests with Hull City and Barcelona.

Manchester City never recovered from falling behind to Leicester in their 3-1 defeat last weekend and Arsenal seemed determined to avoid the same fate, quickly pushing the visitors onto the back foot.

With less than two minutes gone, Alexis Sanchez threw himself at Alex Oxlade-Chamberlain's corner and headed wide, with N'Golo Kante surviving a penalty-box handball appeal shortly after.

Leicester goalkeeper Kasper Schmeichel then raced out boldly to prevent Aaron Ramsey reaching Ozil's pass and within seconds Vardy had forced Petr Cech to save with a downward header at the other end.

It proved the pattern of the first half. Arsenal attacked -- Wes Morgan blocking from Olivier Giroud and Sanchez, Giroud twice heading off-target at corners -- and Leicester countered, Kante obliging Cech to claw the ball away from his top-left corner with a curling shot.

As half-time drew Leicester went ahead, Vardy luring Nacho Monreal into a challenge and then tumbling to the ground before picking himself up and slotting his 19th goal of the season past Cech.
                  
- Koscielny injury -                  
                  
The Leicester end erupted. Arsenal's fans, convinced that referee Martin Atkinson had been hoodwinked by Vardy, booed the officials off at the interval.

There was a further blow for the hosts at half-time as Laurent Koscielny was forced off with a dead leg, which brought Calum Chambers into the fray.

Arsenal might have conceded another penalty when Riyad Mahrez threw himself to the deck after being nicked by Monreal, but referee Atkinson shook hs head.

Instead, after Ramsey had drilled wide and Giroud had headed another chance over, their luck changed when Simpson was shown a second yellow card for tugging Giroud back, five minutes after his first for tripping Sanchez.

The two managers rearranged their teams for the final half hour, Ranieri sending on Marcin Wasilewski and Demarai Gray in place of Mahrez and Shinji Okazaki, Wenger throwing on Walcott for Francis Coquelin.

It was the Arsenal change that was to prove telling, Walcott equalising nine minutes after coming on by side-footing home after Giroud masterfully nodded Hector Bellerin's cross into his path.

It was Arsenal's first shot on target and their attempts to register another proved fraught.

Mertesacker glanced a header just wide and Schmeichel pulled off a pair of brilliant one-handed saves to thwart Giroud and Sanchez.

But with full-time beckoning, Welbeck rushed in to meet Ozil's free-kick with an unerring downward header, eclipsing Leicester's fairytale with one of his own.