Chelsea had two players sent off and lost out to a Heidar Helguson penalty in a heated west London derby.
Helguson won the spot-kick after he was pushed by David Luiz and then beat Petr Cech, who got a touch on the effort.
Jose Bosingwa was sent off for bringing down Shaun Wright-Phillips when through on goal and Didier Drogba was then dismissed for a lunge on Adel Taarabt.
Nicolas Anelka wasted a headed chance late on as the visitors pushed for an equaliser but Rangers held on.
The Chelsea players appeared to take little notice of their manager Andre Villas-Boas who warned before the match of the "emotional challenge" they faced, with the tight stadium at Loftus Road and the added intensity of the derby.
In the end a lack of discipline proved costly with seven bookings and two red cards.
His counterpart Neil Warnock got his tactics spot on as the home side prevented Chelsea from getting into any sort of groove in the first half.
Chelsea struggled to keep possession as QPR harried and chased at every opportunity, giving their opponents no time on the ball.
The home side grew in confidence and took the lead after only nine minutes, from their first foray into the penalty area.
Luiz struggled with the movement of Helguson in the box, as he collected a long ball and the Brazilian barged him over, leaving referee Chris Foy little option but to point to the spot.
Taarabt thought he should take the resulting spot-kick but Helguson won the battle and beat Cech from the penalty spot, although the keeper did get a touch he could only palm the ball into the roof of the net.
Rangers continued to push as the visitors struggled against the power of their opposition.
The challenge was made even harder for Chelsea on 29 minutes when Bosingwa was shown a straight red card.
The Portuguese defender was battling with his former Chelsea team-mate Wright-Phillips, who was through on goal, before he went down under the pressure.
Foy was quick to produce the red card for denying the goalscoring opportunity although the decision seemed harsh.
Chelsea were then reduced to nine men on 41 minutes when Drogba was instantly dismissed for a reckless tackle.
There was no question over the red card this time, as Drogba went in two-footed on midfielder Taarabt.
Half-time could not come quickly enough for Villas-Boas to try to reorganise his side.
Whatever he said seemed to work as Chelsea started the brighter in the second period, Frank Lampard seeing a header deflected wide before Branislav Ivanovic forced a good save from Paddy Kenny.
The Blues felt they had two good appeals for a penalty as they continued to press for an equaliser.
Lampard was brought down by Fitz Hall inside the box, while Luiz appeared to be held by Helguson - referee Foy waved away the protests.
With only 10 minutes to go they had their best chance to equalise.
Ivanovic swung in an excellent ball on to the head of Anelka but his effort was straight at an alert Kenny.
Three minutes later and the visitors went close again when Luiz hit an overhead kick, but Lampard, placed in front of the goal, deflected the ball over the bar.
Luiz, Raul Meireles, Ashley Cole and John Terry were all booked in the closing stages as things threatened to boil over.