Of course, clubs suffer far worse outcomes than merely missing out on the Barclays Premier League title and there is the need for some context here, but it was impossible not to feel utterly dejected when the Sunderland fans made it abundantly clear that something rather dramatic had occurred deep into stoppage time at the Etihad Stadium.
I sometimes think about how celebrating a disallowed goal always feels unfair. I still have nightmares that Teddy Sheringham's equaliser against Bayern Munich in 1999 is flagged offside. I imagined, admittedly with little sympathy, how Liverpool's supporters must have been upset when Luis Suarez's last-minute derby 'winner' at Everton was chalked off as they momentarily enjoyed that moment.
But, for a minute or so, it seemed United had won the league. Not scored a goal, nor won a game, but something fans of a certain age only dreamed of achieving during the barren league run in the 1970s and 1980s. For a very short period of time, we were champions.
As I watched a couple of fans at the front of the away end jumping up and down like crazy, I could only assume QPR had secured a draw. But devoid of access to any information from Manchester City, aside from the murmurs passing around the ground, we could only endure the most anxious of waits to clarify what was happening elsewhere. The ripple of mock joy that then swept through the stand adjacent to the Reds followers soon put paid to the thought that, against all the odds, the 20th title was in the bag.
Even after a short period of reflection, Sir Alex conceded he would not forgive the Sunderland fans' reaction that day, although he's since accepted it's the nature of all football supporters today. And he's right. One look at Twitter shows you how revelling in rivals' misery can mean just