Watford blew the chance to secure their survival in the Coca-Cola Championship as Akos Buzsaky gave QPR a 1-0 victory at Loftus Road.
The Hornets made the short trip to west London knowing a win over a team already safe from the drop would ensure they too stayed up.
With his side no longer in danger, Rangers boss Neil Warnock was even considering blooding the club's youngsters over their remaining games.
But out of respect to the relegation scrap below - not least the struggles of his old club Crystal Palace - he made only two changes, bringing in teenager Antonio German and fellow striker Rowan Vine.
And their victory, courtesy of Buzsaky's first-half penalty, means the agony goes on for the Hornets who are still two points above the drop zone with two games to play.
The goal came when Dusko Tosic's 37th-minute charge into the penalty area was clumsily halted by Hornets right-back Adrian Mariappa, allowing Buzsaky step up and tuck his 12th goal of the season past Loach.