Rangers, who had slipped into the drop zone after a defeat to Newcastle in their last outing, looked nervous early on but gradually asserted themselves to score a win which piles on the problems for Wigan manager Roberto Martinez.
While QPR moved up to 16th place, Wigan are now firmly anchored to the foot of the table, four points adrift of safety.
Rangers took the lead on 32 minutes when Icelandic veteran Heidar Helguson stroked home from the penalty spot after James McCarthy had inexplicably handled inside the area.
Rangers were then cruising on the stroke of half-time when a sublime free-kick from Hungarian international Akos Buzsaky flew in to make it 2-0.
But a resurgent Wigan responded well after half-time, and Martinez's men were thrown a lifeline when Hugo Rodallega pulled a goal back to make it 2-1 on 66 minutes.
QPR's fans were then made to endure a nervy spell when Helguson's second penalty of the afternoon was saved by Ali Al-Habsi to keep Wigan in touch.
But Wigan's lingering hopes of a fightback were snuffed out nine minutes from time when Tommy Smith lashed home a long-range effort to make it 3-1.
Source: AFP
Source: AFP