Angry West Brom supporters turned on manager Steve Bruce as Swansea grabbed a late goal to win 3-2 at the Hawthorns.
Substitute Michael Obafemi scored in the 89th minute after Karlan Grant had missed a late penalty for West Brom to make it back-to-back victories for Russell Martin’s side.
That prompted chants of ‘You’re getting sacked in the morning’ to Bruce from both ends of the ground.
West Brom have won just once in the Sky Bet Championship this season, and not for six games.
Up until the winner, goalkeeper Steven Benda, on his 24th birthday, had looked to be Swansea’s hero after saving Grant’s poor 81st-minute spot kick.
Matt Sorinola went close for Swansea before he gave them a sixth-minute lead as Albion goalkeeper David Button quickly went from hero to zero.
First Sorinola’s close range volley was superbly tipped around the post by the goalkeeper, who then completely missed Ryan Manning’s corner to allow Sorinala to chest the ball into an empty net.
It was the eighth time Albion had conceded first in 11 Championship games this season, six of which have come in the first 15 minutes.
Grady Diangana missed the chance to equalise when he delayed his shot after Benda sliced a clearance and was out of position when Brandon Thomas-Asante closed him down.
Diangana then turned provider but the finish from Jed Wallace left a lot to be desired as the winger mishit his shot from 12 yards out.
The pattern continued as Diangana’s corner – flicked on by Conor Townsend – hit Thomas-Asante and landed safely in Benda’s arms.
Diangana’s deflected cross teed up Wallace but he screwed his angled shot horribly wide from close range.
Loud boos greeted the half-time whistle after West Brom’s appeals for a penalty were waved aside by referee Graham Scott. Thomas-Asante had appeared to have been wrestled to the ground by Kyle Naughton tussling for Wallace’s cross.
West Brom were level within three minutes of the restart.
Jake Livermore, making his 199th League appearance for the Baggies, sidefooted home from 10 yards after his header from John Swift’s corner went to Tom Rogic, who was dispossessed.
Diangana put his side ahead for the first time in the 65th minute.
The former West Ham winger placed an angled low drive through Nathan Wood’s legs and beyond Benda after Wallace cut inside and squared across the box.
Swansea equalised in the 71st minute. Substitute Oliver Ntcham, who replaced Jay Fulton five minutes earlier, skipped inside Diangana before rolling a low left-footed shot in off Button’s left-hand post from 20 yards.
West Brom squandered the chance to regain the lead when substitute Grant missed an 81st-minute penalty after he had been shoved by fellow sub Armstrong Okoflex.
Instead it was Swansea who won it when Obafemi turned smartly past his man on to Ntcham’s pass to sidefoot past Button.
