There are more than one hundred years of grudges and bad feeling between the two famous clubs of Manchester but just for good measure last night Carlos Tevez added a new chapter all of his own.
It will, in years to come, provide some great memories for City fans providing they can negotiate the second leg of this Carling Cup semi-final at Old Trafford a week today for which their Argentine striker has given them a precious lead. Tevez scored two immaculately-taken goals and gave Gary Neville some stick as well, which all added up to a perfect night for the average City supporter.
Tevez took the opportunity after both goals to rub his former employers' noses in it, although he could claim some degree of provocation. After he scored his first from the penalty spot, Neville responded with a simple but easy-to-understand gesture as his former team-mate ran towards him: he gave the City striker the finger.
When Tevez scored his second after the break he already had his celebration in mind, pushing team-mates out the way to stand in front of the United bench with his hands cupped behind his ears. If you think you have seen that one before, you have. Tevez did the same to the Old Trafford directors' box after a goal against City last season and by last night his protests were starting to get tiresome.
What was not in doubt was that an already edgy atmosphere has been given a new dimension by Tevez, the man who crossed the city from the red side to the blue last summer. Having played for them for two years Tevez would do well to remember that the time to stick two fingers up to United is when they are definitively, irrevocably beaten – not when they have 90 minutes at home to rescue the tie.
As for Neville, the photographs that caught him giving Tevez the finger like a moody teenager at a bus stop hardly demonstrate a great deal of maturity for a 34-year-old professional footballer. In fact, the older Neville gets the angrier he seems to be. Sent off earlier in this competition against Barnsley, he seems determined to live up to the grumpy old man stereotype he has cultivated his entire career.
With Old Trafford behind them a week today, there is no telling how United will respond but it will have to be a huge improvement on their lacklustre second-half performance last night. Leading through Ryan Giggs' goal on 16 minutes they looked reasonably comfortable until Tevez equalised and United's confidence evaporated.
They could point to a late rally during which Antonio Valencia missed a glorious opportunity to equalise but as usual it was led by Wayne Rooney who, along with Giggs and Patrice Evra, seems to be his team's only real hope going forward.
It was one of those special nights in Manchester when all the old enmity came bubbling to the surface in spectacular fashion. City dimmed the lights for the pre-match "Blue Moon" anthem and United's fans stole the show by lighting red flares they had smuggled into the stadium. There was an edge.
Ferguson abandoned his Carling Cup kids, Darron Gibson, Danny Welbeck and Gabriel Obertan, who were not even in the squad. Without Nemanja Vidic and Rio Ferdinand they still look vulnerable but City have their injury and availability problems too. The Belgium Under-21 international Dedryck Boyata started in the centre of City's defence for only the second time in his career and he struggled at times.
It was United who controlled most of the first half. Roberto Mancini switched Pablo Zabaleta into the middle of midfield and put Gareth Barry out on the left, presumably to deal with Valencia. This was the 27th time in his career that Barry had faced United and the first time he was on the winning side.
United's goal started with a ball from Evra out to Valencia on the right. Craig Bellamy mistimed the tackle and found the ball slipped through his legs. Valencia's cross took a deflection before Rooney got a touch on it, Shay Given saved and Giggs tucked in the loose ball.
Tevez was untidy with the few early chances that fell his way in the early stages of the first half but Wes Brown and Jonny Evans never looked completely comfortable against him. The breakthrough for City came when Bellamy finally got around the outside of Rafael da Silva on 42 minutes and was dragged back not once but twice.
It was for the second grapple that referee Mike Dean judged to be just inside the area, that he gave the penalty. When he scored – and he did so emphatically – there were vigorous celebrations from Tevez on the touchline.
The momentum that United had built up dissipated and when they came out for the second half, Ferguson's team had all but lost their way. City scored a second on 65 minutes when United again failed to clear a corner. This time Zabaleta headed the ball down to Vincent Kompany who got the ball back across the face of the goal and Tevez nicked in to score at the near post.
Shaun Wright-Phillips had a shot saved before United came back. Nedum Onuoha kicked a shot from Michael Owen, on as a substitute, off the line in the 71st minute. Rooney forced another good save out of Given before Valencia's late miss left the tie still very much in the balance.
Manchester City (4-4-2): Given; Richards, Boyata (Onuoha, 69), Kompany, Garrido; Wright-Phillips (Sylvinho, 79), De Jong, Barry, Zabaleta; Bellamy, Tevez (Benjani, 79). Substitutes not used: Ireland, Robinho, Taylor (gk), Petrov.
Manchester United (4-5-1): Van der Sar; R da Silva (Diouf, 90), Brown, Evans, Evra; Valencia (Scholes, 88), Fletcher, Carrick, Anderson (Owen, 72), Giggs; Rooney. Substitutes not used: Neville, Park, F Da Silva, Kuszczak (gk).
Referee: M Dean (Wirral).
Number of times Gareth Barry faced United before finally being on the winning side.