A goal down after Gianfranco Zola's freakish first-half free-kick, and a man down after Vieira picked up the eighth and possibly softest of his Arsenal red cards, the champions found yet new reserves of the fighting spirit which Arsene Wenger is so fond of extolling.

But if the nature of the comeback was familiar, the saviour was an unlikely one - Ivory Coast youngster Kolo Toure capping a hyperactive substitute's display with his first Gunners goal on the hour mark.

Last weekend Wenger's side recovered from a predicament of their own making to salvage a point at West Ham, and their latest escape act on the other side of the capital came in the face of a limp refereeing performance from Andy D'Urso as well as their opponents.

D'Urso was at best inconsistent, and he compounded his decision to send Vieira off for two borderline bookings by failing to dismiss Sylvain Wiltord, who had already been booked, for a far more blatant misdemeanor on William Gallas late on.

Chelsea meanwhile, other than a flurry of pressure immediately after Zola's opener, were a tepid force and will scarcely get a better chance to put one over on their north London rivals, who were without injured pair Thierry Henry and Dennis Bergkamp as well as losing Vieira for the best part of the second half.

Claudio Ranieri bit the bullet and dropped Jimmy Floyd Hasselbaink to the bench after a lacklustre draw at Southampton, but even after the Dutchman's late introduction, his side's unimaginative approach play in the final third played right into the hands - and onto the head - of the outstanding Sol Campbell.

The Italian swung it goalwards, and as the conspicuously unmarked Gudjohnsen busied himself in font of David Seaman, the England keeper was sufficiently distracted to allow the ball to leap beyond his sluggish grope.

Jesper Gronkjaer came close to doubling the lead before the interval, and the Dane was again involved in the game's pivotal moment five minutes after the restart, falling to the turf after Vieira hung a foot out at his clearance.

Off went Vieira amid much finger-jabbing, but if Stamford Bridge expected a cakewalk to victory, it was much mistaken.

As at Anfield last season, having just nine colleagues brought the best out of Kanu, who began to link well with the tireless Wiltord, while Toure was doing his best impression of a one-man team with his boundless enthusiasm.

It was he who began and ended the move which led to the leveller, feeding Ashley Cole wide on the left before haring into the box to head home after Wiltord's volley had been pushed out by Carlo Cudicini.

Toure came closest to a winner, belting a 45-yard set-piece narrowly over Cudicini's bar with his colleagues expecting a cross, while Campbell dealt easily with the best Chelsea had to offer thereafter.