Keane was afforded a rapturous reception by the Red Devils faithful before the game and his name was chanted at regular intervals throughout.

And the Irishman looked set to take a point back to Sunderland as an added momento of the day until Saha, a half-time replacement for Brazilian new-boy Anderson, glanced home Nani's corner 19 minutes from time to score his first Barclays Premier League goal since December and ensure United did not lose any more ground in the title race.

It was a gut-wrenching blow for Keane, although the Black Cats boss admitted Saha's introduction changed the game in his old club's favour and they had been given a warning just before the Frenchman's matchwinner when Nemanja Vidic fired over from a similar position.

Still, Keane was not dispirited enough to turn down his old boss after the final whistle.

"He has asked me in for a drink and I will go," he said.

"What happens at Manchester United is none of my business. I am sure they will be all right but the result probably overshadowed the day.

"I didn't really get sucked into it or bogged down by the fact I was coming back.

"I appreciated the reception. The United fans have always been good to me, even when I let the club down when I was a player.

"But I am disappointed by the defeat because I felt we could get a positive result."

While Keane declined the opportunity to offer an opinion on United's stuttering form, he could only agree with the overwhelming evidence that Ferguson's side require a direct centre-forward rather than an array of attacking players that like to drop deep.

After a tepid opening period, Saha's introduction sparked them into life.

Carlos Tevez was instantly a changed man, and with Saha's strength and pace extending Sunderland's defence more than at any previous stage, space began to appear in the Black Cats half.

"Louis Saha made the obvious difference when he came on," said Ferguson.

"He gives us strength and penetration and he got us the goal.

"I didn't want to start with him but at half-time I thought he was needed.

"He is different from the rest of our players and, for the first time, they looked pretty edgy at the back."

The victory, following on from an equally narrow win over Tottenham last weekend, at least allows United to keep pace with their major rivals.

And, when they visit Everton in a fortnight, Cristiano Ronaldo will be back from suspension, Saha should be fitter after his long absence, Ryan Giggs will probably have recovered from the minor hamstring strain that kept him out of today's encounter and maybe, even, Wayne Rooney will be available as he continues to make progress in his recovery from a broken foot.

"The international break has come at a good time for us," he said.

"It will give us a chance to get well prepared for the Everton game because the players we have to come back will make a difference."

Keane now finds himself in the unfamiliar position of losing four games on the trot, something he has probably not experienced since his Nottingham Forest days.

Yet, with Liverpool and Manchester United among their opponents, Keane is not getting too stressed about the situation.

"It would be nice to have four victories but I am quite comfortable with where we are," he said.

"It was always going to be a testing time for us.

"We did well for 70 minutes today but the game lasts for 90.

"We almost got there. That is the nature of the Premier League - one slip and you lose the game."

After his meeting with Ferguson, Keane was due to catch up with Ole Gunnar Solskjaer, who, like his former captain, was afforded a standing ovation as he bid farewell following his retirement, which was announced earlier this week.

Although the manner of their departures were somewhat different, Keane can still relate to Solskjaer's predicament and while the former United skipper was notoriously reluctant to hand his phone number out to team-mates, the popular Norwegian is clearly someone he does get on with.

"It was great to see Ole on the pitch," he said.

"I have been in touch with him for most of the week. Hopefully I am going to see him later on."