Liam Rosenior struck the winning penalty for Bristol City, but the game hinged on a 104th minute sending off of QPR's Richard Langley.
Referee Clive Penton must have seen an off the ball incident between the Rangers midfieder and Bristol City's Tom Doherty and once he had brought play back he dismissed Rangers' best player.
Before that a lacklustre game in front of a record crowd for this round of the LDV Vans Trophy had little to get excited about.
Christian Roberts came closest to breaking the deadlock in the 77th minute with a shot that was too hot for Simon Royce and Albano Correia wasted the rebound as Royce recovered to clear the danger