Just when it seemed as if there was nothing else which this compelling match could produce to shock or thrill, Ryan Giggs scored a simply wondrous extra-time winner to keep Manchester United's dreams of the treble firmly on course.

By the time that Giggs' 108th-minute strike finally settled a titanic FA Cup semi-final replay against Arsenal, the crowd, let alone the players, were exhausted by a breathtaking spectacle which surpassed even the highest expectations.

A quality strike from David Beckham was followed by a deflected equaliser by Dennis Bergkamp, an effort by Nicolas Anelka which was narrowly ruled out for offside, a sending-off for Roy Keane and even a penalty save by Peter Schmeichel deep into injury-time.

But as 10-man United attempted to hold on for penalties in extra-time, Giggs intercepted a wayward pass from Patrick Vieira 10 yards within his own half.

The substitute's burst of speed took him clear of any immediate pursuers before rounding Vieira, then Overmars, then Lee Dixon and Overmars together, before smashing an unstoppable shot into the roof of the net from the tightest of angles.

David Ginola suddenly has a contender for goal of the season and, in terms of importance, it was just as vital as the Welshman's last-minute equaliser against Juventus almost a week ago.

It secured United's place back at Wembley against Newcastle and ended Arsenal's chances of retaining the Double - all with four changes having been made to their starting line-up.

Boss Alex Ferguson reacted to his side's growing fixture pile-up, with possibly 11 games in the next 42 days, by leaving out both Andy Cole and Dwight Yorke from the side, while even Giggs was on the bench at the start.

The most surprising inclusion was that of former Spurs striker Teddy Sheringham for only his seventh start of the season and his first since Boxing Day but Ferguson's decision was fully vindicated.

For within 18 minutes of the kick-off, Sheringham, whose movement was exemplary throughout the first-half, had set up Beckham for an opening goal of pure quality surpassed only by Giggs in extra-time.

Beckham had played the ball into Sheringhan's feet on the counter-attack, received it back in acres of space and struck a right-footed shot from 22 yards almost like a free-kick.

It curled unerringly into the far corner for Beckham's third goal in five games - the first time that the seemingly impregnable Arsenal defence had been breached in 690 minutes of play.

The match briefly fizzed into life, with Schmeichel saving at full-stretch from Bergkamp, Martin Keown blocking out Nicky Butt and Sheringham going close twice.

However, a rash of bookings also followed as the tackles became more full-blooded, with Emmanuel Petit, back after his latest suspension, challenging - fairly - like a man possessed in a bid to reinvigorate his side.

At one point, he burst clear of the United defence and although Schmeichel was initially slow off his line, he still managed to block the Frenchman's shot with his legs before watching Nicolas Anelka drive an effort into the side-netting shortly afterwards.

United re-emerged after the break in an even more uncomprising mood as they thwarted Arsenal's all-too-predictable attacking forays.

And they should have scored themselves when Ole Gunnar Solskjaer escaped the offside trap only to drag his shot harmlessly wide.

Sheringham's vision then set up Jesper Blomqvist, who forced Seaman into a fine reaction save, while both Beckham and Solskjaer came close in a series of counter-attacks at lightning speed.

The match seemed to be slipping inexorably beyond Arsenal's reach as even when Anelka finally had a clear sight of goal, he miscued his shot terribly.

Cue Bergkamp.

The Dutchman embarked on a looping run 25 yards out after being supplied by Nigel Winterburn and shot towards goal to be aided by a huge slice of fortune as the ball took a sizeable deflection off Stam and curled into the far corner of the net.

The match then exploded into bedlam as first Arsenal celebrated a winner from Anelka as he capitalised on Schmeichel fumbling a shot from Bergkamp - only for referee David Elleray to spot the raised linesman's flag.

While many observers believed the officials had erred in the first encounter between the two sides last Sunday when ruling out an effort from Keane, this time they were spot on as Anelka was just offside when Bergkamp had shot.

Then Keane, who had earlier fouled Bergkamp, was shown his second yellow card for a scything late tackle on Marc Overmars with 17 minutes left.

United, who had played against 10 men for most of extra-time in the original game following Nelson Vivas' dismissal, quickly regrouped with Paul Scholes on for Sheringham and Solskjaer supported by Giggs and Beckham out wide.

They were inevitably being stretched by Arsenal's fresher legs though and Phil Neville's tired tackle on Ray Parlour as the midfielder burst into the penalty area inevitably led to the spot-kick almost two minutes into injury-time.

Bergkamp stroked the ball just inside the post only to be denied by a world-class save by Schmeichel, who raised his arms in triumph and was engulfed in congratulations by his relieved team-mates.

And so, for the second time in four days, to extra-time as Arsenal pressed forward in ever increasing numbers.

Bergkamp was again denied by Schmeichel's reflexes, injuring his groin in the process, but the Dane still managed to keep out a corner which viciously deflected towards goal off Ronny Johnsen.

On came Kanu as Arsenal went in search of victory only to be denied by Giggs' wondrous late solo effort.

There was still time for the Gunners to equalise but Tony Adams headed wide and Anelka shot well off target.

A handful of on-pitch scuffles between rival fans at the end threatened to marr the occasion but they were soon contained and this was, thrillingly, United's night. Bring on Juventus.

Teams

Arsenal: Seaman, Dixon, Winterburn, Vieira, Adams, Ljungberg (Overmars 62), Anelka, Bergkamp, Keown, Parlour (Kanu 105), Petit (Bould 119).

Subs Not Used: Vivas, Lukic.

Booked: Keown, Parlour.

Goals: Bergkamp 69.

Man Utd: Schmeichel, G. Neville, P. Neville, Johnsen, Stam, Beckham, Butt, Keane, Blomqvist (Giggs 61), Solskjaer (Yorke 91), Sheringham (Scholes 76).

Subs Not Used: Van Der Gouw, Irwin.

Sent Off: Keane (74).

Booked: Stam, Keane, Beckham.

Goals: Beckham 17, Giggs 109.

Att: 30,223.

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