Tjaronn Cheri proved the star turn as an enterprising QPR overcame playoff hopefuls Birmingham at Loftus Road.
But there was a nasty moment after Rs went 2-0 ahead from a penalty at the School End that saw a coin thrown at Rs players.
It was the part of the ground populated by City fans, and the club were quick to issue a statement acknowledging the incident.
"The club will continue to review video footage and liaise with the Metropolitan and West Midlands police," it finished.
Dutchman Chery was a decent finisher when he bagged the opener, a lead doubled by Junior Hoilett, before showing their more familiar pragmatic side after the break.
Rangers started brightly, but Chery’s shot deflected wide was the only cause for concern for former Manchester United keeper Thomas Kuszczak in the first half hour.
It turned out to be a dress-rehearsal as seven minutes later James Perch robbed Ryan Shotton down the Rangers left and when he played the ball in from the by-line the Dutchman span and fired across Kuszczak to the far corner.
Michael Morrison bundled Sebastian Polter over in the box and though the Blues’ man somehow escaped with a yellow Hoilett exacted further punishment, sending Kuszczak the wrong way from the spot.
Birmingham were a different proposition immediately after the break with Jonathan Grounds’ shot blocked from an early corner and when the ball came back out Jacques Maghoma’s goal-bound strike was headed off the line by Karl Henry. David Cotterill’s free-kick was then parried away by Alex Smithies.
At the other end Luongo’s shot forced Kuszczak to tip over and from the resulting corner he did brilliantly again to parry Gabrielle Angella’s header to safety.
Kuszczak denied Chery once more with another fine stop, but Birmingham continued to threaten with Clayton Donaldson and Paul Robinson both going close before the home side’s win was confirmed.