QPR carved out just their third win of the Premier League season at Southampton to renew hope of avoiding relegation.
Loic Remy struck against the run of play after 14 minutes to take the lead, but Saints equalised through Gaston Ramirez before half-time.
Jay Bothroyd tapped the ball home from close range to restore the lead, and fine saves from substitute goalkeeper Rob Green, on for the injured Julio Cesar, helped the west London side through to a vital win.
Southampton were left to rue the fact that they did not capitalise on all their pressure on their bottom-of-the-table opponents, who lustily celebrated their first win in two months.
With so much hanging on this game, the return of Harry Redknapp to St Mary's for the first time since his ill-starred year as Saints' manager added even more spice and the QPR boss received a predictably hostile reception from some sections of the home support.
The home side ignored the day's added context to start confidently, with Adam Lall...