Manchester City maintained its supremacy over fierce rival Manchester United in unconvincing style on Sunday, winning a frenetic derby 1-0 through Sergio Aguero's second-half goal after playing with an extra man for more than half the game.
Chris Smalling's 39th-minute sending-off for two quick yellow cards and an injury to fellow center-back Marcos Rojo at the start of the second half left United with a makeshift defense that held out until the 63rd minute.
The resistance was broken when Aguero turned home a cut-back from Gael Clichy for his league-high 10th goal of the season.
United was the more dangerous side in the last 20 minutes and the final whistle was greeted with relief by City fans, who have seen their side win four straight league matches against their biggest rival for the first time since 1969-70.
"We played very, very well until we scored a goal," City manager Manuel Pellegrini said. "For different reasons, we dropped a little bit more than we needed, we lost the high possession of the ball we had before that. It is normal in a derby."
City ended a three-match winless run in all competitions but is still lacking the intensity and ruthlessness it showed in winning the league and League Cup last season. The gap to unbeaten leader Chelsea is six points whereas ninth-place United is 13 points off the pace - with just half the points of Jose Mourinho's side - despite a summer outlay of about $250 million.
It is United's worst start to a league season after 10 games since 1986.
"I have seen the willpower of this team that I said to the players is fantastic," United manager Louis van Gaal, "but we have still only 13 points out of 10 games and that is not so much."
Smalling's red card was a turning point in a typically frantic, high-tempo derby, although City had already taken command by that point with United goalkeeper David de Gea saving twice from Aguero and also point blank from Jesus Navas in a three-minute spell.
Booked needlessly in the 31st for impeding an out-of-hand clearance by goalkeeper Joe Hart, Smalling dived into a challenge on James Milner eight minutes later and knew what was coming from referee Michael Oliver.
"The second yellow card is a stupid yellow card," Van Gaal said.
"When you have a yellow card," he added, "you have to deal with that. You know that. You cannot do what he has done with the second yellow card. That is not very smart."
The visitors survived until halftime, somewhat fortunately as Rojo - as the last man - appeared to foul Yaya Toure in the final seconds. But their situation became even more critical at the start of the second half when Rojo was carried off on a stretcher with a left shoulder injury in the 55th following a challenge with Martin Demichelis.
For the final 35 minutes, United's unfamiliar defense contained two midfielders, in Antonio Valencia at right back and substitute Michael Carrick at center back, and two 19-year-olds in second substitute Paddy McNair and left back Luke Shaw.
It was always going to be a struggle for United to hold out and Aguero was not to be denied.
A searching pass from Toure found Clichy - a last-minute call-up after Aleksandar Kolarov picked up an injury in the warmup - and the left-back's cross from the byline was steered in by Aguero, who moved beyond Diego Costa as the league's top scorer.
It was only then that United started to create chances, with Angel Di Maria bringing a sprawling save from Joe Hart and Marouane Fellaini heading wide when meeting a cross from Di Maria.
Navas struck the post at the other end but United was pressing more when the full-time whistle was blown. United is nearer the bottom three than the top three after more than a quarter of the season.
"We are very close but not close enough," Van Gaal, "and we have to make steps still to improve."