Rangers reserves went down to a 42nd minute strike from Gary Hart against Brighton at Loftus Road.
A young home side, which included debutant Adam Miller, were undone when Arthur Gnohere allowed a punt upfield to drift over his head before Hart nipped in to finish past Superhoops goalkeeper Jake Cole.
Rangers plugged away in search of an equaliser but got little change from a solid Brighton reaguard, marshalled impressively by the experienced Kerry Mayo.
The home side lined up in a 4-4-2 formation and a scrappy first half was only briefly lit up with efforts for either side from Miller, which went just wide, and Hart whose first time strike was well saved by Cole.
Otherwise the opening period was a muted affair with Rangers only coming to life after Hart's goal.
Luke Townsend struck a low effort straight at the keeper and Miller kept the Brighton defence on their toes as the half time whistle approached.
In the second period Brighton held firm but in truth, they were rarely threatened as, once again, Rangers relied on nothing more than the occasional half chance.
The Superhoops' young strike pairing of Luke Townsend and Shabazz Baidoo ran themselves in to the ground but never got the better of their more experienced opponents.
Adam Miller was substituted on the hour after a pleasing display and Arthur Gnohere soon followed.
He hobbled from the pitch after taking a whack to his right knee although the Rangers medical team have confirmed that his departure from the game was merely precautionary and they are hopeful that he hasn't suffered anything more serious.
But for Miller, it was all about pulling on the blue and white hoops, seven days after playing against Rangers for Aldershot at Loftus Road.
He said: "It was great to be playing here today, looking up and seeing my old seat that I used to sit in when I was a fan. The speed with which everything has happened this week is unbelieveable.
"I thought Brighton were quite defensive today and they were quick to close us down in that respect.
"Last week I was playing with a team who I've been with with for a long time. But today I was playing with a lot of youngsters and although I thought we did well, we don't know each other's game yet. But that will come."
Rangers:
Cole, Johnson, Murphy, Kanyuka, Gnohere (Craig), Mulholland, Donnelly, Miller (Farr), Branco, Baidoo (Zadkovich), Townsendunused subs: Thomas, Judge