There was a time, of course, when Celtic were making loud noises about joining the Premiership. Loud because it seems to be in their genes that nothing should be done quietly when it comes to their beloved club.
The decibels at Old Trafford were cranked up to a level that has not been heard here for many years and, when the shouting was done, the beery hordes of green-and-white-hooped disciples were entitled to feel their team had done enough to reignite the case for an Anglo-Scottish league.
For the time being it remains a hypothetical debate. Yet the Celtic chairman, Brian Quinn, seems determined to keep the idea bubbling away judging by some of his remarks before the match.
Gordon Strachan's players showed, at the very least, that their chances of surviving in English football might be considerably better than many imagine, and their supporters helped concoct an atmosphere that seemed a world away from the dreary hush at Stamford Bridge when Chelsea met Werder Bremen on Tuesday night.
The official number of Celtic fans inside Old Trafford was just under 6,000. Unofficially, it was maybe twice that amount with the same again locked outside. Manchester United v Celtic is a ticket tout's dream and before kick-off there were long queues outside their open-air offices on Matt Busby Way.
Some of the more prized seats were going for more money than a season ticket at Old Trafford costs. Loan sharks had been visited, houses remortgaged. If Celtic ever truly get a team to match their crowd they will need an aircraft hangar to store all the trophies.
But wait. Should the Scottish champions really take such pride that their fans are more famous than their players? There were few distraught Wolverhampton Wanderers supporters, for example, when Lee Naylor left for Celtic Park last month. The shock waves were not felt around Europe when Mark Wilson joined from Dundee United for £500,000 in January.
Strachan has assembled a modest, competent side but nothing more. They are willing yet limited pros. The truth is that it was always going to need an abject performance from United if their opponents were to remember this occasion as anything other than a chastening experience.
In that respect, Celtic ought to be grateful that Rio Ferdinand is still, at 27, liable to the loss of concentration that might be expected of a teenager.
Ferdinand has played so many games now it is probably time we stopped wondering when he is going to grow out of this habit. Yet it is still remarkable that the most expensive defender in Britain can be turned as easily as he was by Jan Vennegoor of Hesselink for the opening goal.
Ferdinand even had the gall to look accusingly at Edwin van der Sar for his failure to keep out the shot. Van der Sar will probably wince, too, when he sees the replays, but the culpability was Ferdinand's and it summed up the sloppiness of United's early play. Alex Ferguson's eyes were burning holes in everyone. The United manager had instructed his players not to be suckered into a Battle of Britain slugfest.
Strachan, on the other hand, had told his players they were representing not just Celtic but the whole of Scotland. In which case their nation can be as satisfied as it is possible in the face of a defeat. There are many Scots, of course, who hate the way their teams are often portrayed as gallant losers, but consider, too, the players at Strachan's disposal.
His first reaction to going 3-2 down was to bring on Paul Telfer, formerly of Coventry City and Southampton. At this level Celtic really need to be more refined than that.
As Jock Stein once said: "We have the best supporters in the world, but I've never seen a fan score a goal."
Guardian Service