Bottom club Queens Park Rangers held Premier League champions Manchester City to a draw, thanks to a fantastic goalkeeping display from Julio Cesar.
The visitors dominated the first half as Pablo Zabaleta hit the bar and Gareth Barry had a shot tipped wide.
Rangers were a danger on the break, with Adel Taarabt and Loic Remy going close either side of half-time.
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QPR continued to stand firm in the second half, with Cesar denying David Silva from six yards.
But a point was the very least Rangers deserved for a spirited defensive display as they stretched their unbeaten Premier League run in 2013.
Since the turn of the year, Harry Redknapp's side have beaten Chelsea and held both Tottenham and West Ham - and this was another performance of real substance.
City looked like overwhelming Rangers in a dominant first-half performance, but the hosts grew in confidence and stature as the game wore on and continue to offer their supporters hope they can win their battle against relegation.
Martin KeownBBC Radio 5 live
"You have to say it was QPR's night. There were so many good performances, and tonight could be the night that Man City feel the Premier League slip from their hands."
They had their chances, with Joleon Lescott shooting over the bar after a rare mistake from Cesar and Zabaleta rattling the woodwork with a header from 12 yards after good work by Silva.
Javi Garcia, playing at centre-half in place of the injured Vincent Kompany, also fired wide from 30 yards as City poured forward in the early stages.
While City were dominant in midfield, Taarabt and Remy were a constant threat on the break.
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First, Remy capitalised on a quick free-kick to break clear and have a shot deflected wide, before Taarabt countered and forced a fantastic sprawling save from Joe Hart.
Both chances came against the run of play and City looked like taking the lead when Carlos Tevez pulled the ball back for Barry - only for Cesar to tip the England midfielder's 18-yard shot wide.
QPR were content for the visitors to dominate possession, often having all 11 men back behind the ball. The tactic began to bring reward as City struggled to unlock the Rangers defence, which was well marshalled by Ryan Nelsen on his final appearance for the club before leaving to take over as manager of Toronto FC.
Aguero, who famously scored City's late winner when they won the Premier League title with victory over QPR on the final day of last season, was not as clinical and he blazed over from 12 yards.
Edin Dzeko, so often City's saviour from the bench, was brought on and he looked like finally breaking Rangers' resistance when he pulled the ball back for Silva, but the Spanish playmaker saw his six-yard shot spectacularly saved by Cesar.
Both sides had late penalty shouts, with Remy and Scott Sinclair going down in the area, but referee Phil Dowd waved away the appeals.
And while Rangers were left delighted with another gutsy point at the final whistle, City were hoping Manchester United fail to capitalise and stretch their lead at the top of the table to seven points against Southampton on Wednesday.
QPR manager Harry Redknapp:
"Of course it is a bonus point, it is a great point.
"They rip teams to pieces home and away, you would take a point off them at any time. It is a fantastic result.
"I wouldn't say it is the end (of the title race) - it is a good result for Fergie (Sir Alex Ferguson) tonight for sure, but it is still open."
Manchester City manager Roberto Mancini:
"We lost two points, this is sure. We played well, we had the chances but didn't score - that is all it is.
"We are disappointed with this result because we had a lot of chances to win, we dominated this game but when you play like this and don't score quickly it can be difficult.
"QPR defended very well and got players behind the ball and Julio Cesar was incredible tonight."
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