It was the result neither side wanted but even Manchester United were unable to loosen Arsenal's vice-like grip on the domestic Double in their FA Cup semi-final at Villa Park.

The Gunners endured their 10th sending-off of the season when Nelson Vivas was dismissed four minutes into extra-time, were outplayed for long periods but still tenaciously emerged unscathed to set up a replay on Wednesday.

While United will rue a host of missed chances, their anger at a controversial first-half decision which ruled out a Roy Keane `goal' was undiminished even at the final whistle.

Referee David Elleray, who had an inconsistent game throughout, deemed that Dwight Yorke had been offside in the build-up to the strike even though the linesman first raised then dropped then again raised his flag.

Although Arsenal had two late opportunities to claim an unlikely victory, their seventh consecutive clean sheet was built around the heroic efforts of centre-backs Tony Adams and Martin Keown and the tireless running of their midfield.

United's treble dream may still be alive but Emmanuel Petit will be back for the replay and their players looked to be tiring in extra-time against a side who they have failed to beat in their past six meetings.

Chelsea boss Gianluca Vialli and perhaps Juventus coach Carlo Ancelotti will have been the only men celebrating at the final whistle as United have another fixture in a packed season.

However, with neither of the Premiership's top two having lost a single game this year, a replay had always seemed the most likely outcome.

After an exemplary minute's silence by fans to mark the 10th anniversary of the Hillsborough disaster, the tie immediately burst into life amid a series of bruising challenges.

Gary Neville and Vivas were booked in the first six minutes and David Beckham only just escaped after apparently elbowing Nigel Winterburn in the ribs.

The game nevertheless flowed from end to end with Jaap Stam and Adams both making important interceptions, while Keane and Vieira, both full of running, provided a bulwark in front of them.

Chances came sporadically as Ryan Giggs blasted a shot well over from just 12 yards out and Peter Schmeichel tipped a header from Tony Adams over the bar before then denying Bergkamp. Just as it seemed as if the frenetic early pace had taken its toll though, United looked to have taken the lead on 38 minutes through Keane.

Giggs played the ball outside Lee Dixon on the left flank and, with Yorke in an offside position inside him as he tried to hold his run, the linesman immediately raised his flag only to put it almost straight down again. He raised the flag once more when the former Aston Villa striker _ by now clearly onside - then flicked on Giggs' ensuing cross towards Keane, who blasted his shot into the roof of the net.

But after consulting his assistant, Elleray seemed to agree that Yorke had earlier been interfering with play - despite the linesman having apparently changed his mind. The decision incensed the United players, who berated both officials at length, and Denis Irwin was booked soon afterwards before escaping another yellow card moments later for a tackle from behind.

United had nevertheless seized the initiative and Cole then put Yorke clear just inside the penalty area but he could not get the ball out from his under his feet and fluffed it straight along the ground into David Seaman's hands.

The furious protests continued as the half-time whistle blew but United were straight back on the offensive after the interval as they strung together a series of vibrant moves and Vivas escaped a second yellow card for a trip on Keane.

Keown and Adams continued to stand resolute though and even when Cole was set through by Giggs, he wastefully miscued his shot straight at Seaman. Once again the match started to drift as the tempo dropped, fouls went unpunished and both sides lacked width, with Arsenal increasingly bereft of attacking ideas.

Keane headed straight at Seaman from Yorke's cross, Beckham struck a free-kick inches wide, Giggs directed another dead-ball effort straight at the keeper and Anelka blazed wildly at a chance after bouncing off Stam's challenge.

However, for all United's late pressure, the match was heading inexorably towards extra-time. With Marc Overmars already off injured, Arsenal were further weakened four minutes into added-time by Vivas' sending-off for his second yellow card - an off-the-ball elbow into Beckham's face.

United, with Paul Scholes and Ole Gunnar Solskjaer now both on, still failed to make the most of their extra man or the increasingly open spaces and their frustration showed as Neville flung the ball away and himself only just escaped a second booking.

Both sides had half-chances with Stam blocking Bergkamp's effort and Yorke firing wide but with three minutes left, it was substitute Fredrik Ljungberg who raced through on goal after being put through by Bergkamp. Schmeichel saved brilliantly with his legs and it took a last-ditch block from Neville to deny the Dutchman himself as he threatened to dribble his way through the entire United defence.

So it is back to Villa Park in three days for another titanic tussle. At least there has to finally be a winner then.

Teams

Man Utd: Schmeichel, G. Neville, Irwin (P. Neville 84), Stam, Johnsen, Beckham, Butt, Cole (Scholes 112), Keane, Yorke, Giggs (Solskjaer 98).

Subs Not Used: Van Der Gouw, Blomqvist.

Booked: G. Neville, Irwin.

Arsenal: Seaman, Dixon, Winterburn, Vieira, Adams, Vivas, Anelka (Kanu 98), Bergkamp, Overmars (Ljungberg 90), Keown, Parlour.

Subs Not Used: Bould, Grimandi, Lukic.

Sent Off: Vivas (95).

Booked: Vivas, Parlour.

Att: 39,217

Ref: D Elleray (Harrow-on-the-Hill).