YOUSSOUF Mulumbu’s brilliant 85th-minute solo strike earned Pepe Mel his first Albion win at the eighth time of asking.
The Baggies fell behind in less than two minutes to Roland Lamah’s individual effort and were somewhat fortunate to only be a goal down at half-time.
But Mel’s men were a transformed outfit after the break and their positive start yielded an equaliser after just six minutes.
Stephane Sessegnon, making his first start since New Year’s Day after a groin injury lay-off, rifled the visitors level from 25 yards – his third goal of the campaign and first in four months.
And there was even better to come when Mulumbu placed the most precise of shots from similar distance in off the right-hand post five minutes from time.
It was just reward for the fantastic following from the Black Country, who remained patient and roared the visitors to victory.
Albion also deserve great credit for the way they shook off a stuttering first 45 minutes to achieve a gutsy fifth league win of the campaign.
During the pre-match warm-up, the Baggies players wore branded t-shirts as they got behind Swansea’s annual ‘Let’s Kick Racism Out of Football’ day.
Albion were backed by a sell-out 2,000-strong following at the Liberty Stadium, no doubt boosted by the club’s decision to subsidise ticket prices.
And there were plenty of Spanish flags in the away end as a show of support for head coach Mel.
With injuries biting hard, Mel made four changes – three enforced. Craig Dawson, James Morrison, Sessegnon and Graham Dorrans - making his first Barclays Premier League start since August - earned recalls. Making way were injured trio Chris Brunt (knee), Claudio Yacob (hamstring) and Morgan Amalfitano (knee), plus the benched Zoltan Gera.
There was also a big moment for 20-year-old Albion Academy product Liam O’Neil, who was named on the bench for a senior match for the first time.
Fourteenth entertained 17th in South Wales, with the two teams separated by only four points.
And it was the hosts who looked like stretching that gap as they opened the scoring inside less than two minutes.
Lamah looked like he had a lot to do as he raced onto Wilfred Bony’s angled pass down the left, but the wideman cut inside Steven Reid before rifling inside the far post from the tightest of angles.
It was another body blow to Albion’s already-fragile confidence, but Mel’s men took their medicine and gradually regrouped.
And it was the visitors who recorded the next effort on goal, albeit 13 minutes after the Swans’ opener. Following neat build-up play, Morrison fed Victor Anichebe who showed brute strength to spin Ashley Williams on the edge of the box before firing fiercely into Michel Vorm’s midriff.
However, Albion owed a huge debt to Ben Foster for keeping the deficit to a single goal when he produced a stunning point-blank save to deny Bony from Lamah’s left-wing centre.
The action swung to the other end and Sessegnon fired wide on the half-volley from 25 yards.
There was a nice ebb and flow to the game now and Gareth McAuley, making his 100th start for the club, had to produce a vital block to prevent Lamah’s 15-yard effort from troubling Foster.
Lamah was proving a real handful and, on 23, he would have been disappointed not to even hit the target with a far-post header from Jonathan de Guzman’s corner.
Swansea were now beginning to get on top and the unmarked de Guzman wasn’t too far away from getting a goalscoring touch to Wayne Routledge’s terrific low cross.
Mel’s former Real Betis charge Jose Canas tried his luck with an ambitious volley on 30 but saw his 25-yard effort looped harmlessly over Foster’s bar.
The action certainly wasn’t all in the Baggies’ half, but the men from the Black Country were struggling to get any change out of the Swans’ rearguard.
Albion survived two scares inside the 36th minute. Bony hacked horribly wide after ghosting in behind Reid, who passed a late fitness test yesterday, to chest down Routledge’s cross. Moments later, the off-balance de Guzman stabbed wide from another dangerous Lamah centre.
Williams was also holding his head in his hands on 44 when he directed a free header from de Guzman’s flag-kick into the ground and over the bar.
That proved the final action of a half from which Swansea would have felt aggrieved they only had one goal to show for their efforts.
Albion started the second half on the front foot and Dawson went close when he controlled Dorrans’ corner just inside the Swansea box and saw his right-footed shot blocked in a crowded goalmouth.
The Baggies had looked ‘more at it’ since the interval and restored parity on 52. After tigerish play by Morrison, Sessegnon controlled the ball 25 yards out and whipped an unstoppable right-footed shot inside the bottom left-hand corner.
Swansea carved out an immediate opportunity to regain the lead when Bony won a free-kick on the edge of the Baggies’ box. Foster, however, was equal to de Guzman’s effort, saving high to his right.
Buoyed on by a crescendo of noise from the end they were now attacking, Albion kept coming forward. Anichebe, who put in a selfless shift, tried his luck from 25 yards on 59 but his right-footer screwed high and wide.
Anichebe then set up Sessegnon but his scuffed 18-yard effort was easily gathered by Vorm.
However, Albion had a lucky escape on 62 when de Guzman’s eight-yard shot struck McAuley’s arm at point-blank range. In the defender's defence, he knew little about it and referee Martin Atkinson waved Swansea's penalty appeals away.
But normal service soon resumed as Mel’s men again camped in the Swansea half. The next goal was going to prove pivotal and Anichebe again proved a handful when he spun on Morrison’s pass and bundled a right-footed shot wide from 18 yards.
Foster had to come to Mulumbu’s rescue on 70 when the Baggies midfielder was dispossessed by de Guzman. The Swans midfielder powered into the box before seeing his 15-yard shot superbly blocked by the England international.
But the DR Congo international more than made up for his lapse – by firing a dramatic 85th-minute winner. Mulumbu picked up the loose ball just inside the Albion half before driving forward and placing the most audacious of shots in off the right-hand post from 20 yards.
With 89 minutes on the clock, Mel showed real faith in O'Neil by handing him his first-team debut in the most nerve-wracking of circumstances.
But the Academy product did not let his head coach down. O'Neil made a couple of vital contributions as Albion saw out the win with little trouble.
SWANSEA (4-2-3-1): Vorm; Rangel, Amat, Williams (c), Davies; Britton (Emnes 87), Canas (Michu 63); Routledge, de Guzman, Lamah (Hernandez 77); Bony. Subs not used: Tremmel (gk), Tiendalli, Taylor, Lita.
ALBION (3-5-1-1): Foster; McAuley, Olsson (c), Dawson; Reid, Morrison, Mulumbu, Dorrans (Gera 75), Ridgewell; Sessegnon (Thievy 79); Anichebe (O’Neil, 89). Subs not used: Myhill (gk), Vydra, Berahino, Sinclair.
GOALS: SWANSEA – Lamah (2). ALBION – Sessegnon (52), Mulumbu (85).
BOOKINGS: SWANSEA – Routledge (foul 28). ALBION – Anichebe (foul 26), Reid (foul 42), Olsson (foul 53).
REFEREE: M Atkinson (West Yorkshire).
ALBION STARMAN: Ben Foster.