Sir Alex Ferguson's decision to celebrate his 70th birthday by hinting that he would like at least another three years in the job backfired quite badly, not least when it emerged that his bizarre starting line-up, with Antonio Valencia and Michael Carrick in the back four and Rafael da Silva in midfield, was at least in part due to his own disciplinary stance against Wayne Rooney, Jonny Evans and Darron Gibson for celebrating their 5-0 Boxing Day win over Wigan by going out for a meal.

If that appears to have been an over-reaction on Ferguson's part, he also risked understatement by describing some of his recent setbacks as minuscule. "I am still enjoying it," he said in a birthday interview with MUTV. "We have had defeats but compared to what we have achieved they are minuscule."

Broadly that is still true and no one could doubt that an almost bottomless fund of goodwill exists for Ferguson at Old Trafford, though the sentiment would have been less kindly viewed at the end of the afternoon than at the outset. United were attempting to put pressure on their neighbours and rivals by retaking the Premier League's top spot, after all. A humiliating defeat by the bottom club, complete with an inadequate performance by the latest expensive goalkeeper, was not on anyone's agenda. And could that 6-1 home defeat by City in October really be written off as minuscule? Or the humbling Champions League exit at the hands of Basel? "The proof of the pudding will be our results," Ferguson had suggested, after rhetorically asking whether a 70-year-old was fit to be in charge of such a great club. In which case, this was not the most auspicious of starts to an eighth decade.

Invited to sum up Blackburn's chaotic season in three words, Steve Kean chose just one. "Rollercoaster," said the only Glaswegian manager left with anything to celebrate after a remarkable New Year's Eve. "We are in the wrong place in the table, not where we want to be at all, but you can see the lads are giving it everything. I am under no illusions that even results like this will win the supporters at Ewood round but all I can say is, if we carry on like this, I hope the fans will get behind us. I wouldn't imagine any true Blackburn supporter would want to see us relegated."

Blackburn supporters have not been demonstrating in favour of relegation, of course. They have been demonstrating against Kean because they believe relegation will be the certain consequence of the club's know-nothing owners keeping faith with an inexperienced manager. This result should give them pause. Kean might not be the problem. One of the first games the people from Venky's saw after their takeover of the club was the corresponding fixture last season, when Blackburn under Sam Allardyce went down 7-1. With Phil Jones now playing for Manchester United, the bottom team beating the one attempting to go top and emerging talents such as Grant Hanley, Adam Henley and Jason Lowe outshining some of the more illustrious names on the home teamsheet, one could see why Kean likened his occasionally scary season to a switchback ride.

Yet in terms of ups and downs, Ferguson could give his fellow Scot a run for his money. This was supposed to be all about the birthday boy but from the momentthe Old Trafford crowd failed to join in with a choral rendition of Happy Birthday – it is hard to imagine that happening at Anfield – there was a sense that things could go badly wrong. Sure enough, as the ground began to empty some minutes before the end of the game, the Blackburn fans drowned out the muted home groans and jeers with a sarcastic but spirited version of Happy Birthday Dear Fergie.

Blackburn defended solidly and took the lead from a set piece, just as they had done in gaining a draw at Liverpool on Boxing Day, when Dimitar Berbatov conceded a penalty by pulling down Chris Samba at a free-kick. Ferguson corrected some of his positional aberrations at half-time but still saw the visitors pull further ahead when Yakubu Ayegbeni made short work of beating Carrick, Jones and then David de Gea.

Berbatov's fifth and sixth goals in three games appeared to have set up the usual grandstand finish – both Kean and Ferguson thought there would be only one winner once United got back to 2-2 – but it did not work out that way. An enterprising run from Henley won a corner, from which Hanley outjumped the flailing De Gea not once but twice to score the winner.

"The third goal killed us," Ferguson said, slightly surprisingly as there were still 10 minutes plus Fergie time remaining. Yet many United fans did not even wait for Fergie time. They had seen enough. It was odd that United fans should be sneaking off early while the Rovers fans were left celebrating but presumably that is why Kean made reference to a rollercoaster.

Playing like this, United will struggle to keep up with the neighbours but, if Blackburn can keep it up, they have every chance of escaping the bottom three. "It is great to get off the bottom," Yakubu said. "Credit to the Blackburn fans at Old Trafford, they supported their team. This could be a fresh start for us, if we want to stay in the league we must start winning our home games. Another two wins in a row and we will be fine."