West Brom midfielder Graham Dorrans added to QPR's relegation fears with a superb winner in the Barclays Premier League clash at the Hawthorns.
The Scotland international settled the contest midway through the first half with a 30-yard strike.
But QPR should have picked up at least a point with Bobby Zamora causing plenty of problems but spurning several opportunities.
Mark Hughes' side have strung together some impressive results at Loftus Road in recent weeks to revive their hopes of staying up.
But they have now failed to win in 11 away matches and picked up only two points.
Albion have now moved past the 40-point mark and can look forward to a third successive season of top flight football.
Youssouf Mulumbu made his presence felt in midfield while left-back Liam Ridgewell again showed he was an astute signing by Roy Hodgson from Birmingham in January.
QPR started brightly and Zamora went close to putting them ahead after only two minutes.
The England striker found himself with only Ben Foster to beat after the ball ricocheted invitingly into his path.
But Foster was alert to the situation and came quickly off his line to block the shot at the expense of a corner.