Iain Dowie suffered his first serious setback as boss at Loftus Road as Rangers surrendered their unbeaten home record.
Late goals from Martin Albrechtsen and Emanuel Villa - following corners - gave Derby County a 2-0 win as Rangers failed to cash in against a side who won only three away points all last season in the Premier League and had yet to win on the road in the Championship.
Dowie lamented the number of unforced errors made by his team, who failed to live up to the expectations generated by a previously flawless home record, by the superb 1-0 win at Aston Villa in midweek and by the prospect of taking on Man United at Old Trafford in the next round of the Carling Cup.
Rangers could not subdue Derby's tenacity and organisation and the fluency that has brought them goals aplenty up to now deserted them.
The closest they came was an Emmanuel Ledesma strike which deflected against a post.
"We couldn't get up a head of steam," Dowie declared. "We've conceded goals from set pieces, which is really galling and must bounce back on Tuesday against Blackpool."