Neil Warnockâ€™s Râ€™s recorded their first win at home this season thanks to Heidar Helgusonâ€™s 10th minute penalty as two Blues players â€“ Jose Bosingwa and Didier Drogba â€“ were shown straight red cards prior to half-time.
In the first league meeting between the London foes since 1996, the home side were awarded a penalty when David Luiz clattered into the back of Helguson who picked himself up to chip into the back of the net despite the best efforts of Blues keeper Petr Cech.
Bosingwa was given his questionable marching orders just over 20 minutes later, when he denied Shaun Wright-Phillips a goalscoring opportunity when he was last man in defence just outside the area, before Drogba received the same fate for his reckless 41st minute two-footed challenge on Adel Taarabt.
Despite the disadvantage of being two men down, Chelsea were actually the better side in the second half and were quite unlucky not to equalise on a number of occasions, particularly when substitute Nicolas Anelka had a great chance when Branislav Ivanovic found him with a brilliant cross with the outside of his right foot but the Frenchmanâ€™s header was straight at Râ€™s gloveman Paddy Kenny.
Moments later, Anelka stood it up for Luiz whose acrobatic overhead kick was on target but took a deflection off Frank Lampard and went over the bar as QPR came away with a win for the history books as Chelsea missed out on the chance to go third with just their second loss of the campaign.
Yellow cards: QPR - Shaun Derry 52â€™, Joey Barton 59â€™
CHE - John Obi Mikel 50â€™, Frank Lampard 52â€™, Branislav Ivanovic 58â€™, David Luiz 70â€™, Raul Meireles 72â€™, Ashley Cole 76â€™, John Terry 90â€™
Red cards: CHE - Jose Bosingwa 33â€™, Didier Drogba 41â€™