Sir Alex Ferguson congratulated Manchester City on snatching the Barclays Premier League title in a dramatic conclusion to the season - but warned them it would take a century to match Manchester United's record.
For a fleeting moment Ferguson and his players thought they had pipped their arch-rivals when the final whistle at the Stadium of Light confirmed a 1-0 victory over Sunderland.
However, City, who just minutes earlier had been trailing 2-1 at home to 10-man QPR, won it at the death when Edin Dzeko and Sergio Aguero scored in stoppage time to claim a first title in 44 years on goal difference.
Ferguson said: "We congratulate Manchester City. Anyone who wins the league deserves to win it because it's a very, very difficult league to win.
"We know that because, as we've experienced today, we've lost on goal difference.
"They [City] can go on as much as they like. That's what you would expect, but the history of our club stands us aside.
"We don't need to worry about that. I think we have a rich history, better than anyone, and it will take them a century to get to our level of history.
"But for us it's still a challenge and we're good at challenges. We'll kick on from here."
On a day when United's fate was decided elsewhere, Ferguson's men upheld their part of the bargain.
Rooney's 20th-minute header, his 35th goal of the season, was ultimately enough to claim the points, although his side might have won even more comfortably had it not been for the excellence of Sunderland goalkeeper Simon Mignolet and the woodwork.
However, it was all to count for nothing despite United hearing the final whistle believing they had won the title, only to learn within seconds that City has snatched it from their grasp in what has become known as "Fergie time".
The presentation ceremony which was being prepared behind the scenes was quickly abandoned to leave United wondering what might have been.
Ferguson told Sky Sports: "We knew five minutes' extra time was being played at City. Our game had three minutes stoppage time.
"You don't know what can happen in the extra two minutes, but they got that break and won the game.
"It is a cruel way to have the title ripped away, but I've had a lot of ups and downs in my 25 years here.
"Today, we nearly did it and I would like to say on behalf of Manchester United, congratulations to our neighbours."
In the end, the derby rivals finished level on 89 points, with City triumphing on goal difference.
Ferguson added: "At the start of the season, if I remember correctly, I said 82 points would probably win the league this season and we are seven points ahead of that.
"But look, it doesn't matter, we've lost the league."
For Sunderland boss Martin O'Neill, the late twist took him back to the day in 2003 when his Celtic side lost the Scottish title on goal difference on the final day.
He said: "The last couple of minutes in the match really is something that has taken me back a few years to my season at Celtic when we lost on goal difference.
"They are just about the most harrowing thoughts you can have. You immediately start thinking about goals you could have scored during the course of the year.
"You could have done all of those things and it comes down to the last couple of minutes.
"Wayne Rooney is playing the ball into the corner thinking they have won the game and that's going to be enough, obviously.
"They have done their bit and then to hear the news coming through was really just unbelievable."