Mark Warburton admitted QPR deserved to lose to Leyton Orient in the Carabao Cup first round but was pleased they kept their nerve to triumph in a penalty shoot-out.
Rob Dickie scored for the second consecutive game after 16 minutes to put the R's on course to claim bragging rights in the London derby, but missed first-half opportunities opened the door for the O's.
The Sky Bet League Two club belied their divisional status with a superb display after the break and Aaron Drinan levelled in the 76th minute to force penalties, but Ruel Sotiriou hit the crossbar from 12 yards and Albert Adomah netted QPR's fifth spot-kick to earn a 5-3 penalty success.
Warburton said: "After a very bright start, we had to be more ruthless. We should have been out of sight after 25 minutes and we got very loose and complacent.
"We have to do better and second half we were the team under pressure and we should have lost that game of football."
Backed by a large travelling contingent, enjoying a first away trip following the R's since March 2020, the Championship side were able to keep their heads in the shoot-out.
"We had 1,800 QPR fans which is a magnificent turnout and we have a responsibility to put on a performance," Warburton admitted.
"But the players stepped up and put the penalties away with aplomb and you saw what it meant for Albert at the end, being a QPR fan."
Orient manager Kenny Jackett urged his squad to take confidence from their performance.
He said: "We maybe lacked some confidence but once we settled down and believed in ourselves more, we gave them problems.
"We have to build on that performance now. We are disappointed to go out but that second half we need to build on."
