Manchester United suffered a setback to their title hopes as they were beaten by derby rivals Manchester City.
Benjani (centre) scored for Man City on his debut
A poignant minute's silence and tribute to the Munich air disaster victims took place before a game which saw Darius Vassell's strike put City ahead.
United became stifled by a staunch City side who extended their lead with a glanced Benjani Mwaruwari header.
United struggled overall but got a consolation goal when Michael Carrick shot into the corner in injury time.
The hugely emotive occasion had begun in moving scenes at Old Trafford in respect to the 23 - of which eight were players from the Old Trafford club - who died in the Munich air disaster on 6 February 1958.
United's players wore 1958-style sponsorless red shirts numbered one to 11, while City also wore special shirts.
United manager Sir Alex Ferguson and counterpart Sven-Goran Eriksson each laid a wreath either side of the centre circle before an impeccably observed minute's silence.
The disruption to the silence feared beforehand did not materialise and, instead, the clubs paid their respects as the city came together to produce a touching tribute before the game got under way.
United appeared in determined mood and quickly set about City and put the visitors on the backfoot.
A piercing Nani ball found Carlos Tevez and he crossed to the far post for the unmarked Ryan Giggs, whose acute-angled strike was tipped over by keeper Joe Hart.
City slowly began to gather themselves but were given another scare when Micah Richards was outpaced by Tevez only for fellow centre-back Richard Dunne to retrieve the situation by blocking the United striker's shot.
Richards survived a handball shout just outside the City area before the visitors broke United's brief early grip.
Martin Petrov slid a defence-splitting pass into Stephen Ireland's clever run and his poked shot was blocked by on-rushing keeper Edwin van der Sar.
The ball fell to Vassell and he powered in at the second attempt after his first strike was blocked by Van der Sar.
Ronaldo gives a sign of Man Utd's frustration against Man City
A Tevez turn and shot was parried away by Hart, Cristiano Ronaldo had a shot deflected wide by Dunne and Nemanja Vidic poked as United attempted to equalise.
But City were disciplined and organised as they kept United, who seemed to get more affected by the occasion after going behind, at bay.
And they shocked the hosts again with a second on the stroke of half time.
Left-winger Petrov was a constant threat to United with his pace and delivery and he crossed from the right for Benjani to glance in a header across goal.
Dietmar Hamann had a sweetly struck half-volley saved immediately after the break but City sat back as they soaked up the pressure and tried to catch United out on the counter-attack.
Richards and Dunne were immense for City at the back as they refused to give an out-of-sorts United any kind of sight on goal with a powerful performance.
Giggs did get a rare chance for the home side but his angled shot went wide as United's threat decreased as the game wore on and any expected pressure did not materialise.
Carrick's consolation strike from 18 yards came too late for United, who were without Wayne Rooney and lost their first game at home in the league this season.
City's win saw them complete the first league double over their arch-rivals for the first time since the 1969/70 season.
Man Utd: Van der Sar, Brown, Vidic, Ferdinand, O'Shea (Carrick 73), Nani (Park 64), Scholes, Anderson (Hargreaves 73), Giggs, Ronaldo, Tevez.
Subs Not Used: Kuszczak, Simpson.
Goals: Carrick 90.
Man City: Hart, Onuoha, Richards, Dunne, Ball, Vassell, Ireland, Hamann (Jihai 84), Gelson, Petrov (Garrido 87), Mwaruwari (Caicedo 75).
Subs Not Used: Isaksson, Geovanni.
Goals: Vassell 25, Mwaruwari 45.
Ref: Howard Webb (S Yorkshire).
BBC Sport Player Rater man of the match: Man City's Martin Petrov 7.81 (on 90 minutes).Please note that you can still give the players marks out of 10 on BBC Sport's Player Rater after the match has finished.