Manchester City made the most of a stupid error in judgement from Manchester United defender Chris Smalling to earn a 1-0 victory at the Etihad this afternoon, but their narrow margin of victory indicates just how nervy a finish Manuel Pellegrini's men endured to the season's first derby clash.
Smalling was sent off before half-time after being booked twice in the space of seven minutes, both after frankly avoidable lapses in concentration.
The England international blocked Joe Hart's goal kick before sliding into a rash challenge on James Milner, which laid the foundation for Sergio Aguero to score the only goal of the game after a clever City move.
United manager Louis van Gaal definitely has plenty to ponder after a disappointing afternoon, which leaves the Red Devils with their lowest points total after 10 league games since 1987.
City have now won four Manchester derbies in a row, so let's take a look at which superstars made the difference for better or worse after a frantic afternoon at Eastlands.
Joe Hart: 6
Was a virtual passenger in the second half, but before Smalling's red card made a couple of routine saves. Late saves from Van Persie and Di Maria proved crucial.
Pablo Zabaleta: 7
Swashbuckling full-back grew in stature and benefited hugely from Van Gaal's decision to swap Di Maria to the opposite flank in the second half. Rather fortunate not to be sent off for two yellow cards, with an early escape from the referee's notebook extremely helpful.
Vincent Kompany: 6
Carries a reputation of being very aggressive in big matches and performance showed that again today, for better and worse. Was left for dead late on by both Rooney and Fellaini and was very fortunate not to be punished.
Gael Clichy: 7
Brought into the side after Aleksandr Kolarov suffered an injury in the warm-up, but more than justified his place. Brilliant burst and cross created Aguero's decisive strike and the Frenchman's pace caused problems on the overlap all afternoon.
Again nowhere near his best, but got through plenty of work and remains important to the way Manuel Pellegrini wants to play.
Yaya Toure: 9
Ivory Coast star has been rightly criticised this season, but in potent patches showed why he's an absolute menace in advanced areas this afternoon. Power to run with the ball broke United's line between defence and midfield constantly, while the craft he showed to find Clichy and help Aguero score was top class.
James Milner: 8
Often an unsung hero but deserves credit today, getting through a tremendous amount of work to show just why he's now a regular n Pellegrini's starting XI. Was perhaps brought off far to early when you consider his stamina levels.
Jesus Navas: 7
Mixed bag from the Spanish flier, but his pace gave Luke Shaw problems all afternoon. Very unlucky to smash the post after a brilliant dart inside late on.
Stevan Jovetic: 6
Struggled to make his mark on the match and quickly found himself dropping deep to get involved. Was an odd decision to leave out Edin Dzeko in favour of a different option in attack, one that ultimately didn't really pay off for Pellegrini despite the victory.
Sergio Aguero: 9 (Man of the Match)
Sheer class again from the fantastic South American marksman, who produced a ruthless finish that had all the hallmarks we've come to expect from a world-class striker. Aguero's speed of thought and turn made him a constant menace and in truth he should have won a pair of penalties to go with his goal.
Edin Dzeko: 5 - Very little chance to even get a touch on the ball let alone make an impact.
Samir Nasri: 5 - Welcome return to action for a player who will no doubt be very important for City over the next few months.
Fernandinho: 6 - His introduction did very little to stop nerves spreading fast in the closing stages, and also annoyed star man Aguero in the process.
David De Gea: 7
Made two strong saves in the first half to continue fine run of recent from, but must continue to be dismayed at the defensive deficiencies on show from his vantage point as the last line of defence.
Antonio Valencia: 6
Drafted in to replace Rafael and was definitely at fault for the incident which saw Smalling sent off, choosing to rush out and close down Sergio Aguero rather than mark James Milner. Expect better from such an experienced Premier League player.
Chris Smalling: 3
Hard to defend the England international's stupidity for his first booking, with the decision to block Joe Hart's quick goal kick ultimately costing him dear. Challenge on Milner was also a shocker, a passage of play which saw the centre-back's naive approach exposed.
Marcos Rojo: 6
Shoulder injury will be a huge concern for Van Gaal, but it was a problem all of the Argentine international's own making. Quite why Rojo felt the need to rush out and challenge Martin Demichelis only he will know, but it was rash at a time when United needed cool heads.
Luke Shaw: 6
The £27m million man stood up to the test of dealing with Jesus Navas and the constantly onrushing Pablo Zabaleta well early on, but was at times left with very little in the way of support as the match progressed.. Smalling's dismissal effectively ended the youngster's chances of looking to bomb on and influence play in the opposition half, which is one his great strengths.
Daley Blind: 5
Another United player who failed to deal with the occasion, booked very early on after deciding to go to ground from behind Yaya Toure. Dutchman was a virtual passenger from that point on, but in fairness a congested midfield area made things very difficult.
Marouane Fellaini: 6
Made a bright start in possession and used his physical presence to stay involved, but in truth was very lucky not to concede a penalty after kicking Aguero inside the box without getting anywhere near the ball. Faded thereafter and spurned a terrific late chance to equalise.
Adnan Januzaj: 5
Sacrificed once Smalling was dismissed, although in truth he had no affect on the game up to that point. His inclusion also made life difficult for Valencia at right-back, primarily due to a lack of protection. Young Belgian also had very few options on the rare occasions he did get possession in an advanced position.
Wayne Rooney: 6
Played in a midfield three and showed desire to track back and help out in his own half, as a lung-busting chase to catch the advancing Toure showed early in the second half. Passing was far from sharp though, which is perhaps a consequence of his enforced spell on the sidelines. Brilliant late run could have saved the day, but why he didn't shoot is a question only he can answer.
Angel di Maria: 5
Argentine maestro produced a pair of sumptuous crosses from dead-ball situations early on, but was surprisingly poor in terms of getting back to do his defensive duty the other way. His decision not to track the runner following Toure's brilliant pass to create the opener was a poor one.
Robin van Persie: 6
Had virtually no service to work with and still managed to look sharp on occasions, in particular forcing Joe Hart to make a smart stop midway through the second half. Dutchman's talents look absolutely wasted in a lone front role though it has to be said.
Michael Carrick: 6
Thrown in to the mix for the first time this season once Smalling was gone, didn't look up to the pace of the game as a result.
Paddy McNair: 5
Youngster came on to replace Rojo and in truth it was always a damaged limitation exercise. Left brutally exposed by mistakes elsewhere as tired legs prevailed.
James Wilson: 5
Made one exciting run out wide to win a late free kick, which could have been massive for United on a different day.