Tore Andre Flo made a dream debut for Sunderland - but Manchester United captain Roy Keane stole the headlines with a red card.

Norwegian striker Flo, signed just before the transfer deadline, hauled the Black Cats back into the game after they had fallen behind to a Ryan Giggs goal.

United, for whom David Beckham was outstanding in midfield, were left to rue a host of missed chances.

And their frustration finally boiled over when Keane was sent off for elbowing Jason McAteer in the dying seconds.

The former Republic of Ireland team-mates had been involved in an earlier spat before the red mist descended on Keane.

Sir Alex Ferguson's side, who suffered a further blow with the loss of defender Mikael Silvestre to injury, will now have to regroup in time for their game against Middlesbrough on Tuesday.

It took United only seven minutes to open the scoring against their Champions League opponents Zalaegerszeg in midweek.

And they repeated the feat against Sunderland, exploiting a hesitant home defence to take the lead.

Ole Gunnar Solskjaer headed the ball on for Giggs, who ghosted past the Black Cats' back-line and rifled in a low left-foot shot past Thomas Sorensen.

A period of intense pressure from United then ensued and they should really have put the game beyond Sunderland's reach before half-time.

Giggs, Solskjaer and Keane were all presented with chances, but failed to find the target.

For Sunderland, McAteer forced a superb fingertip save from Roy Carroll in the United goal, while Kevin Phillips flashed a shot wide.

And so it proved when the persistence of McAteer down the left provided Flo with his first real opportunity.

The tall Norwegian made no mistake from six yards, striking the ball high into the United goal to send the Stadium of Light into raptures.

Only the alertness of Phil Babb and Sorensen in the Sunderland goal prevented United from stealing a late winner as the visitors poured forward.

But the Black Cats maintained their compusure, unlike Keane, who was unnecessarily dismissed in injury-time.

Sunderland: Sorensen, Wright, Babb, Bjorklund, Gray, Piper (Thirlwell 88), McAteer, Reyna, Butler, Flo (Quinn 79), Phillips.
Subs Not Used: Myhre, Kyle, McCartney.

Booked: McAteer.

Man Utd: Carroll, Phil Neville (Forlan 90), Blanc, Ferdinand, Silvestre (O'Shea 26), Beckham, Veron, Keane, Giggs, van Nistelrooy, Solskjaer.
Subs Not Used: Stewart, Williams, Chadwick.

Sent Off: Keane (90).
Booked: Phil Neville, Beckham.

Attendance: 47,586

Referee: U Rennie (S Yorkshire).