Sunderland - Arsenal missed the chance to go top of the Premier League after Sunderland striker Darren Bent swooped to score a 95th minute equaliser at the Stadium of Light.
The Gunners, down to 10 men following the second-half dismissal of Cameroonian Alex Song, led from the 13th minute thanks to a bizarre goal by the Spain international Cesc Fabregas.
However, the midfielder’s joy was shortlived when he was forced to limp off before half-time with a hamstring injury. And Fabregas now seems certain to miss Tuesday’s North London derby against Tottenham Hotspur in the League Cup.
Sunderland replaced the suspended Lee Cattermole with the Paraguay international midfielder Cristian Riveros while Black Cats manager Steve Bruce chose to leave club record signing and Ghana forward Asamoah Gyan on the bench.
Arsenal, buoyed by Wednesday's 6-0 Champions League victory against the Portuguese club Braga, handed Samir Nasri a first league start since the opening day of the season.
A fast-paced opening saw Sunderland dominate possession and the home team forced a series of early corners with England Under-21 international Jordan Henderson proving more than a match for Fabregas.
The Black Cats, looking for only a fourth home league win in 10 attempts against the Gunners, chose to attack at every opportunity only to concede a freak goal against the run of play.
Central defender Anton Ferdinand hesitated inside his own half before striking his clearance straight at the right shin of the advancing Fabregas. With the Sunderland goalkeeper, Simon Mignolet, 15 yards from his own goal line, the loose ball looped over the Frenchman’s head and into an open goal.
The home side responded immediately and on-loan Manchester City defender Nedum Onuoha should have converted Henderson's right wing corner only to direct a free header over the crossbar.
Fabregas, who had been feeling his left hamstring since opening the scoring, was replaced by the Czech Republic international Tomas Rosicky 16 minutes before half-time as Arsenal continued to feel sustained Sunderland pressure.
Egypt international midfielder Ahmed Elmohamady whipped in an inviting cross from the right and Riveros, signed from Cruz Azul during the close season, spurned yet another clear chance when he mistimed his far post header.
Sunderland, by far the better team before the break, started the second half in sluggish fashion and the Russia international Andrei Arshavin almost capitalised only to see two close range shots shave the woodwork.
Mignolet denied the Morocco forward Marouane Chamakh with a point blank save in the 52nd minute before Arsenal suffered a fresh setback in the shape of the dismissal of midfielder Song.
The Douala-born player had been cautioned before half-time following a series of fouls and his obstruction of the Frenchman Steed Malbranque was deemed a second bookable offence.
Down to 10 men and clinging on to their slender advantage, Arsenal faced a further challenge when Bruce chose to introduce the former Rennes forward Gyan, who replaced Riveros with 26 minutes remaining.
However, Elmohamady's reckless tackle on Nasri in the 74th minute saw referee Phil Dowd award the Gunners a penalty only for substitute Rosicky to blast his first spot kick in an Arsenal shirt high over the bar.
And Sunderland made the most of their unlikely reprieve when Bent pounced on the loose ball in the fifth minute of injury time and fired home his sixth goal of the season with the last kick of the game.