London: Manchester United moved eight points clear in the Premier League title race on Sunday by beating Queens Park Rangers 2-0 while Manchester City, who had Mario Balotelli sent off, crashed to a 1-0 defeat at Arsenal.
With only six matches to play United, who trailed City for most of the season until going top a month ago, have 79 points while their faltering Manchester neighbours have 71.
Arsenal, whose winning goal from Mikel Arteta came after 87 minutes, are third on 61 points, two ahead of arch-rivals Tottenham Hotspur who drew 0-0 at Sunderland on Saturday.
Balotelli, already sent off once this season and banned for a stamp on Tottenham's Scott Parker, now risks missing most of the rest of the run-in because of a lengthy ban.
City manager Roberto Mancini refused to concede the title race was over for his second-placed team.
"It's not over mathematically but it's clear now that it's going to be difficult for us," Mancini told Sky Sports.
"You never say never in football but we must start winning again, beginning on Wednesday at home to West Bromwich Albion."
Mancini appeared to be at the end of his tether when asked about volatile Italian striker Balotelli.
"I defend Mario always because he's a good guy but if he doesn't change in the future he risks wasting his talent," said the City manager.
"I've been with him for two years now and I can do nothing more. I hope for his sake he can start to improve and that he understands he cannot continue to behave like this in the future."
United won at Old Trafford thanks to a dubious 15th-minute penalty from Wayne Rooney and a trademark 68th-minute long-range shot by Paul Scholes.
QPR were reduced to 10 men as a result of the penalty incident when Shaun Derry was sent off for what was the softest of touches on United winger Ashley Young who appeared to dive.