If games of football only lasted for 45 minutes then Manchester City would have won today's enthralling encounter against their elite neighbours in red.
But, as we all know, the game is played for 90-plus minutes. In the end, Manchester United's experience and star quality, in key areas, paid dividends. Wayne Rooney's injury-time winner allowed United to win the all-important home leg 3-1. A trip to Wembley to face Aston Villa in the League Cup final is their reward.
Of course, there are plenty of talking points from the game itself. For starters, there was the excellent referring performance by Howard Webb, who had to deal with a number of tricky player conflicts, such was the intensity and friction of the encounter. Poor leadership here and things would have boiled out of control.
Meanwhile, having two top goalkeepers pulling off a couple of great saves and the effervescent yet irritable Craig Bellamy getting under everyone's skin - apparently not even a coin to the head fazes him - simply added to the occasion. The unruly fans responsible for throwing the coin and bottle projectiles at the fiery Welshman now create a few headaches for United. 'He was getting on our nerves' can hardly be a good defence for the actions and so expect suspensions and fines to follow shortly.
As for the game itself, Manchester City's defensive display in a 4-5-1 formation (4-3-3 when attacking) will be encouraging as they looked solid and compact for large periods and with Pablo Zabaleta in the middle of the park they were sturdier. Stephen Ireland's mettle will now be tested in the coming weeks after Zabaleta was picked over him. Kudos to Mancini for these improvements and also for his lecture to Carlos Tevez to move on from the Gary Neville cat-calling episode leading up to the game. Undoubtedly, Tevez's unsavoury comments ignited this contest before it had even begun. The atmosphere at Old Trafford was at fever pitch and the resolve of the United players to simply not lose was as intense as it would be for any Champions League encounter.
As a consequence it came down to the impact players for United coming through. Ryan Giggs, Paul Scholes, Darren Fletcher, Michael Carrick, and Rooney were on top form and even at the back - which has been an eyesore at times this season - they were determined and solid and rarely penetrated.
For all their tactical savvy and counter-attacking threat, Manchester City simply wilted at the back. They couldn't cope with the constant piercing attacks from United.
Lessons abound for coach Roberto Mancini, who has coped well so far and is full to the brim with class. In the end though, it will be about winning prizes in England, not performing in bits and pieces. As Aston Villa manager Martin O'Neill recently pointed out, it takes a bit of everything to win in England. In reference to Arsenal, he talked about their physicality being the only question mark this season - with Manchester City it is not that simple.
After today's reality of playing well but still losing comfortably, Mancini now has had a taste of just how difficult it will be to win something.