The hosts had gone behind via an Abdoulaye Meite own goal but rallied back through the Nigerian striker and the Congolese midfielder after going a man down with the score level.
The hosts came from behind spectacularly after Abdoulaye Meite had made a hash of a Stewart Downing cross by slicing his clearance into the back of his own goal before Peter Odemwingie scored a second-half equalizer, which was swiftly followed by a red card for Paul Scharner. But Youssuf Mulumbu completed a heroic comeback for the depleted hosts with a late finish.
Baggies boss Roy Hodgson was forced to make changes to his squad with captain Chris Brunt, right-back Steven Reid and Jerome Thomas all missing out through injury. Simon Cox, Gonzalo Jara and James Morrison all stepped in, as Carlos Vela started once more for the hosts.
Gary McAllister, standing in for the unwell Gerard Houllier, made just one change to the side that drew with Stoke last week, bringing Gabriel Agbonlahor back into the fold, with Emile Heskey the man to miss out.
It did not take long for the visitors to open the scoring in a fiery first few minutes but it was a goal that would make three quarters of the ground wince as Downing cut inside on the right and delivered a cross with his left foot that Meite horrendously shinned into his own goal under little pressure.
It was almost two for McAllister's men as Stiliyan Petrov dropped his shoulder to beat his marker before firing in from range, but Scott Carson did just enough to gather it before Darren Bent could pounce on the rebound.
The game continued in a frenetic manner, with West Brom anything but static as it tried to pass and move its way to an equalizer. But Cox failed to pick out Odemwingie as he raced in between Villa's center-backs and then Brad Friedel denied Mulumbu a stunning equalizer by tipping the Congolese midfielder's 25-yard strike just round the post.
The Baggies continued to zip the ball around, with James Morrison and Cox both involved in much of the build-up play, but slack defending at the back from Jara should have been punished by Ashley Young, who cut inside the Chilean before shanking over on his right foot from just outside the area.
A better chance was to come up at the opposite end as Paul Scharner and Odemwingie combined to find Cox, who expertly sent through Vela, but the Mexican on loan from Arsenal went for a spectacular first time lob when the angle was against him, with his effort going well over.
The hosts had an appeal for a red card controversially turned down minutes later as Cox expertly backheeled to Odemwingie in behind Villa's back line before the Nigerian tumbled under a touch from last man James Collins, but referee Phil Dowd brought play back for an offside, with replays proving that the jet-heeled striker was a good yard ahead of the last claret and blue shirt before Cox's flick.
Villa right-back Kyle Walker came close to doubling the away side's lead after bursting down the flank and clipping in a cross that forced Carson to tip over at his near post before Darren Bent did put the ball into the back of the net, only to be ruled offside.
The visitors continued to fly forward though time and again they squandered chances to put a decent ball into the box, and when they did – through Ashley Young – they failed to get a telling touch, while their only other shot of the half, from Downing, rattled the wrong side of the netting.
As Dowd blew for half-time both sets of supporters were on their feet after an attacking display, but the visitors could count themselves highly fortunate to have gone in the lead in the way they did and to have ended the half with 11 men.
Not a quiet opening | Villa took the lead after just five minutes through a Meite own goal
Both managers were forced into making changes just minutes into the second half with Jara and Richard Dunne pulling up and being replaced by Gabriel Tamas and Ciaran Clark respectively.
Vela, who had been lively if not effective, then had a big appeal for a penalty after being slipped through by James Morrison, but Dowd ruled that Luke Young's tackle was well timed, with the defender being at the center of controversy soon after as he stopped Odemwingie in the box.
But the Baggies were to have reason to cheer minutes later as Odemwingie became the club's first player to score in four consecutive Premier League games as he reacted quickest to Scharner's toe poke to slam in from a corner.
Yet the euphoria was to be short-lived as Scharner was swiftly sent off for a second bookable offense after getting both hands around Petrov's waist in the middle of the park.
Robert Pires was swiftly brought on by McAllister for the tiring Nigel Reo-Coker as Villa eyed the chance to push through West Brom's now weakened midfield, while Vela was taken off for Marc-Antoine Fortune as Odemwingie switched to the right flank.
The visitors continued to threaten, but stand-in captain Jonas Olsson and Meite stood firm against a barrage of Walker crosses to prevent Agbonlahor and Bent from making it 2-1, with the Swede particularly commanding.
Downing came close to regaining the lead for Villa with a strike from distance, but incredibly it was 10-man West Brom which would go ahead as Mulumbu latched onto Cox's pass and spun in the box before scuffing it over Friedel and into the back of the net.
It capped a remarkable comeback from a side emboldened in recent months, with the three points all but ensuring its top flight status for next season, while Villa will be worried but about results elsewhere dragging it back into danger.
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