Branislav Ivanovic's first-half cracker and tactical mastery by Jose Mourinho helped classy Chelsea to a 1-0 win at blunted Premier League title rivals Manchester City.
Chelsea's battling win was the first time previously rampant City have failed to score at home this season and sent the Londoners level on 53 points with the second-placed Mancunians, two points behind leaders Arsenal after 24 games.
Ivanovic struck just after the half hour when Ramires' effort was blocked by Vincent Kompany and fell for the Serbian right back, who let fly first time from the edge of the box and saw his powerful left-foot shot nestle in the far corner.
City had chances to equalise but Chelsea, who also hit the woodwork three times, were always a threat on the break in an absorbing contest, which was decided by Mourinho's ability to find the perfect blend between attack and defence.
"We showed a lot of character, and created a lot of chances. We spent a good couple of days working on their strengths and weaknesses - that is typical Jose Mourinho," Chelsea captain John Terry told Sky Sports.
"We have a couple of games at home now to kick on. We must win them as we dropped points against West Ham last week," he added referring to a frustrating 0-0 draw at Stamford Bridge.
Monday's game was billed as a potential early title decider by some, such has been City's incredible form and the widely held belief that wily Chelsea are their most likely challengers despite Arsenal having led the race for much of the season.
In the battle between the team with the best attack and the outfit with the meanest defence in the league, both managers chose a more defensive midfield than usual to try to take charge of the game at the Etihad Stadium.
Centre backs Martin Demichelis and David Luiz were employed in the centre of the park for City and Chelsea respectively and the visitors' playmaker Oscar was left on the bench but the game started openly with both sides having decent sniffs at goal.
Free-scoring City, without injured Argentine talisman Sergio Aguero, threatened when Alvaro Negredo fired over and Yaya Toure twice went close but David Silva had the best opportunity after 18 minutes when his close range finish squirmed wide.
Chelsea continually broke at pace and Ramires tapped the ball into the net with the offside flag raised before having a very good effort saved by Joe Hart after the shaky home defence had fallen away during another foray by the Londoners.
Purists feared the often cautious Mourinho might "park the bus", an accusation the Portuguese coach has used about sides playing too defensively against his team, but instead the game was easy on the eye.
A lively atmosphere in an unusually dry Manchester added to the sense of occasion but there was stunned silence apart from an ecstatic band of away fans as soon as Ivanovic struck the winner having not been tracked by Silva.
"They scored a beautiful goal, not an easy goal, he hit it from a long way out with the outside of his foot but before their goal we had clear chances to score, so I don't think there was a problem with the way we played," City boss Manuel Pellegrini told reporters as he bemoaned injuries in his squad.
"We lost today against a good team who played well but I thought we deserved at least a draw but they had the luck to win it," he said, echoing an accusation Mourinho levelled at City as the mind games gathered pace in the build-up to the match.
Following what turned out to be the only goal, City striker Edin Dzeko blasted over before his opposite number Samuel Eto'o rattled the woodwork from a difficult angle before the interval.
The second half started at a frantic pace with Chelsea again repeatedly worrying the City backline but the hosts were soon up the other end and Toure sent a rasping drive just wide.
Chelsea's January signing Nemanja Matic then clipped the post with a forceful effort from distance, prompting Pellegrini to send on creative forward Stevan Jovetic in place of Negredo in a bid to wrestle control of the match.
It had little effect and soon it was Gary Cahill's turn to strike the woodwork for Chelsea as the home crowd, so used to their side scoring 4, 5 or 6, struggled to comprehend events - even against a team managed by one of the shrewdest around.
Silva had two good chances in the last 20 minutes with City always in the hunt but Chelsea held out for a famous win.
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