The script was written perfectly for Manchester City as Carlos Tevez struck twice against his old club to leave the Blues on the brink of their first domestic final since 1981.
City need to avoid defeat at Old Trafford next week but if this evening's events are any guide, it is destiny that the Blues, subservient for so long - and Tevez, subject of such scorn when he quit Manchester United last summer - will have their day.
Tevez's two goals came after Ryan Giggs had given visitors United the lead, and his delirious celebrations reflected his, and City's, enthusiasm for putting one over on their neighbours.
The friction around the City of Manchester Stadium as the lights were dimmed before kick-off for a rendition of 'Blue Moon' was only made even more intense by a couple of red flares in the visiting end that glowed United's response.
It set the scene for a scintillating encounter between the two halves of Manchester, one potless but loaded, the other using the vast array of trophies as insulation against a chilling debt piling up outside.
For a good half an hour, it appeared Sir Alex Ferguson had got his tactics spot-on.
Although Wayne Rooney was a lone frontman, the extra man further back meant United were able to dominate midfield.
Antonio Valencia hugged one flank, Giggs rolled back the years on the other, and between them Darren Fletcher, Anderson and Michael Carrick passed the ball around City heads going dizzy as they tried to keep up.
Rooney had already been denied from close range once when he got on the end of Patrice Evra's shot, only for rookie defender Dedryck Boyata to make the block.
So when a similar effort from the England star was turned away by Shay Given after Valencia had skipped past his marker, it was a first victory for the Irishman in what turned into a personal duel.
But the rebound rolled into the path of Giggs, the 36-year-old who has appeared in more of these matches than anyone else.
From three yards Giggs could not miss. His first derby goal since 1996.
At that stage, City looked as though they were going to be completely outplayed, but slowly the tide began to turn.
Tevez wasted a glorious chance when Shaun Wright-Phillips picked him out with a superb curling cross, then Micah Richards thudded a headed into Boyata's back after Bellamy had been the provider.
In the end, City needed a controversial penalty to get their equaliser. Controversial in the sense Rafael was outside the area when he began an extended tug of Bellamy's shirt.
The offence was clear enough and as the Brazilian teenager - the one youngster Ferguson eventually picked - was inside the box when he let go, referee Mike Dean felt a spot-kick was the suitable punishment.
Edwin van der Sar used all his experience to try to put Tevez off. But the former United man was not having any off it and eventually stepped up to confidently ram home the penalty into the top of the net.
Tevez had enough dignity not to celebrate directly in front of the fans who bellowed 'Fergie, sign him up' from the Stretford End last year.
But the sight of Gary Neville was too much to resist and Tevez delivered a 'shut your mouth' hand gesture to his former skipper, who backed Ferguson's decision to get rid of the Argentinian.
For all the understandable focus on Tevez, the most influential man on the pitch was Given, who turned away yet another point-blank effort when Giggs got his head to Rooney's deep cross.
The worth of that save did not become apparent until City's next attack when Vincent Kompany hooked a wayward Pablo Zabaleta's shot straight onto Tevez's head.
As he scored and Eastlands erupted, the striker this time immediately raced to the home dug-out and cupped his ears, in exactly the same manner he did when he scored for United in a Premier League meeting between these two sides late last season, when the Old Trafford crowd's demand for him to stay was at its peak.
Just yards away, Ferguson stared straight ahead, chewing his gum furiously. Again the chant was "sign him up". This time it was City doing the singing.
Tevez's work was done. Given still had more to do. Rooney was denied three more times as United laid siege at the end looking for an equaliser.
They still have another 90 minutes to get one. But Tevez will want more as well.Reuse content