Josh Griffiths’ gaffe handed QPR a survival lifeline as West Brom’s fading play-off hopes took another hit.
Chris Martin charged down the goalkeeper’s clearance to score as Rangers came from 2-0 down to salvage a 2-2 draw.
It kept Gareth Ainsworth’s men two points clear of the Sky Bet Championship relegation zone and ended a four-match losing streak.
Brandon Thomas-Asante and Semi Ajayi had put the Baggies in control inside 15 minutes before Lyndon Dykes pulled a goal back.
Albion are now five points adrift of the top six with six games left.
They had raced into a seemingly commanding lead and opened the scoring after 10 minutes.
John Swift’s wicked delivery was missed by Seny Dieng and the ball hit Thomas-Asante’s arm on the line – which was missed by the officials – and went in.
Just three minutes later it was 2-0 when a neat free-kick routine set Marc Albrighton scampering down the right.
His cross found Swift, who was denied by Dieng, but Ajayi followed in to prod the ball over the line.
Yet, if the Baggies thought they were cruising to a comfortable victory they were mistaken as Rangers started their recovery after 22 minutes.
A delicious cross from Ilias Chair was met by Dykes who glanced a brilliant header in from 10 yards.
It put The Hawthorns on edge, with around 200 fans having already staged a pre-game protest against owner Guochuan Lai – although it made little impact.
Conor Townsend dragged wide and Jimmy Dunne came close to a leveller when he headed wide in first-half injury time.
But the Baggies imploded four minutes after the break to give the visitors the equaliser.
There seemed little pressure as Albion kept the ball at the back until Erik Pieters’ loose back pass forced Griffiths to stretch.
His first touch was poor, which allowed Martin to close him down and block the clearance – with the ball flying into the empty net.
The deflated Baggies struggled to rediscover their momentum and QPR were good value for their comeback and nearly snatched victory.
Martin fired off target with 13 minutes to go before Taylor Richards wasted a golden chance with six minutes remaining, heading Jamal Lowe’s cross wide, with Andre Dozzell also going close late on.
