Watching the Manchester United players celebrate in front of the away end after their 3-2 victory over rivals Manchester City on Saturday left a sour taste in the mouth for the home supporters. They'd spent all day gearing up for what they hoped would be the icing on the cake for the season -- winning the title against their local rivals - and, 2-0 up, it looked a dead cert by half-time.
Somehow, from a position of being two goals to the good and having stunned United into submission, City forgot to play the second period and wound up losing a game they should have won. Raheem Sterling (three times) and Ilkay Gundogan (twice) missed golden opportunities to put the match to bed, while the visitors went on to create three decent chances and scored each.
This is what City do: they build you up, to knock you down. Sure, they may be on the verge of the most dominant Premier League title wins the fans have ever seen, and they may have played football the quality of which surpasses pretty much everything that's gone before it, but that doesn't stop the sense of crushing disappointment that follows what happened on Saturday.
Only City could have a spell that feels like attending the club's own funeral while winning a title in record-breaking circumstances in one of the most dominant seasons ever. That's a charm that many other teams' fans will probably never appreciate and one that may get a wry smile at the Etihad, providing it all turns out well in the end.
What Saturday did demonstrate, however, is just how seriously the tables have turned in Manchester. While City have some way to go before they match United's trophy haul of the last 20 years, the roles have clearly reversed. The away end took great delight in reminding the home fans of their previous successes, chanting "20 times" in response to the calls of "we're gonna win the league."
But since the departure of Sir Alex Ferguson, United's fans have been clinging grimly onto that past, while City's have been looking to the future with hope. It used to be the blue half of the city that would celebrate spoiling the party with their one-off derby wins, while the red half claimed there were bigger fish to fry in defeat.
City fans are finally getting to grips with the feeling of having lost the battle, knowing that they'll win the war -- United's supporters vice-versa.
For those suggesting that the away end were treating it like winning a cup final, it has to be remembered that it was unrealistic to expect anything else. United had little else to play for, so having been 2-0 down and chasing shadows for 45 minutes, the celebrations came from the relief of not having lost the title to their most-hated opponents. They'd stopped their rivals winning in what had been described as a "once-in-a-lifetime opportunity."
Equally, though, it's clear why the City fans took at least some small comfort in watching their sheer delight at delaying what is surely an inevitable title win. They've been there so many times before that it's pleasant to see the boot now on the other foot -- those who called out a "small time" attitude in City's similar jubilation at winning past derbies are now having to accept that they're in that same boat.
The biggest reason why Saturday's result was so disappointing for the home support was because it was entirely avoidable -- in a week where City had so badly underperformed in the only other competition they weren't streets ahead in.
If Sterling or Gundogan had found the net at 2-0, the game would have been over. If Martin Atkinson had pointed to the spot when Ashley Young tried to remove Sergio Aguero's lower leg, it could have been a different ending. If Pep Guardiola had made his changes earlier, perhaps City could have wrestled control back and not collapsed in a 15-minutes spell.
The hurt is all about the bigger picture. With City expected to crash out of the Champions League when Liverpool bring their 3-0 first leg lead to the Etihad on Tuesday evening, a title win against their rivals would have been a real pick-me-up that could have made the European tie interesting.
Instead, the momentum is gone and Guardiola is staring down the barrel of three disappointments on the bounce.
All that said, now that the dust has settled on the derby, fans shouldn't feel too disheartened. The United celebrations provided a timely reminder of just how dominant City have been this season and, come the end of May, one disappointing week will not overshadow what's been an extraordinary campaign.