TEN-MAN Albion failed to steal a march on their play-off rivals as Burnley come from two down to edge a controversial five-goal thriller.
The Baggies appeared to be cruising to a third successive win on the road when Jason Koumas and Nathan Ellington both scored their ninth goals of the season inside the opening seven minutes.
Clarets top gun Andy Gray clawed one back in the 16th minute when he netted from an offside position.
And Tony Mowbray's men were on the wrong end of another highly-debatable decision a minute before the break when Paul McShane was harshly sent-off for a mistimed aerial challenge with ex-Baggie James O'Connor.
In the Ireland international's absence, the Baggies looked vulnerable in the air and Burnley made their one-man advantage pay in the 48th minute when Gray levelled the scores.
Albion dug deep but super-sub Chris McCann broke their hearts with an 87th-minute winner to leave the fifth-placed Baggies' play-off hopes delicately balanced, sitting one point above seventh spot.
They left the field reflecting on what might have been had McShane been allowed to stay on.
Mowbray made two enforced changes as Chris Perry ended a five-month wait for a recall to the Baggies' starting XI.
The former Tottenham and Charlton centre-half replaced the injured Sam Sodje (foot) while Koumas came into midfield for the suspended Darren Carter.
John Hartson was handed a bench berth after being included in the Albion boss' 16-man squad for the first time in 11 games.
The Baggies threatened within 18 seconds of the kick-off as Ellington powered down the right and picked out strike partner Diomansy Kamara in the box.
The Senegal pace ace teed up Zoltan Gera but he fluffed his first-time shot wide from 15 yards.
The Clarets replied in the fifth minute when Steve Jones did well to keep a ball in on the left-hand touchline before flashing a dangerous ball across goal, just out of Ade Akinbiyi's reach at the back post.
But it was the visitors who opened the scoring a minute later.
The recalled Koumas collected Gera's lay-off before skipping past two challenges and firing a 25-yard exocet past Brian Jensen, despite the ex-Hawthorns stopper getting a hand to the ball.
It got even better for the Baggies in the seventh minute when Robert Koren found Gera out on the right with a superb crossfield ball.
The Hungarian centred for Ellington to head in off Burnley centre-half Wayne Thomas.
It was a carbon-copy opening to the Hawthorns encounter between the two sides in November when Albion also raced into a 2-0 seven-minute lead thanks to Koumas and Ellington strikes.
But the similarity ended there as Burnley got themselves back in the game in the 16th minute.
Dean Kiely's attempted throw to Kamara in the centre-circle was intercepted by Michael Duff and the ball cannoned through to the unmarked Gray just outside the Baggies box.
The Turf Moor hitman kept his cool to slot home past Kiely, despite the Albion backline's vociferous appeals for offside, which TV replays confirmed were justified.
Perry made a vital challenge on Akinbiyi in the six-yard box in the 25th minute as the former Wolves hotshot threatened from Duff's right-wing cross.
At the other end, Koumas tested Jensen on the half-hour mark but this time the giant Dane was up to the task as he flung himself to his right to beat out the Welsh wizard's 30-yard screamer for a corner.
Albion continued to dictate proceedings but Jon Harley forced his way past Kamara in the middle of the park in the 38th minute before unleashing a left-foot shot across goal from 30 yards.
Koren's sublime aerial ball then fell perfectly for the marauding Martin Albrechtsen, who battled his way past Harley in the box before firing across the face of goal from a tight angle.
Moments later, Kamara was pulled down on the edge of the Burnley box and that gave Koumas the chance to threaten the hosts' goal again as he curled the resulting free-kick just wide of the left-hand post.
But the Baggies suffered a killer blow a minute before the break.
McShane was harshly sent-off for what looked nothing more than an accidental clash of heads with former Baggie O'Connor, who was stretchered off with a head injury and replaced by McCann.
O'Connor's lengthy treatment before his departure gave Mowbray time to move Albrechtsen across to centre-half and slot Jonathan Greening in at right-back as Albion went into the half-time interval with a slender but deserved lead.
Yet it took just three minutes after the restart for Burnley to cash in on their one-man advantage.
Thomas headed down Wade Elliott's corner at the back post and, following a goalmouth scramble, Gray swiveled to bundle the ball home from close range.
Seconds later, Steve Cotterill's men broke again and substitute McCann played Akinbiyi in on the left-hand edge of the box, but his finish lacked power and trickled to Kiely.
Koumas raced down the left wing in the 53rd minute and crossed low into the box, where the hosts needed Steven Caldwell to nick the ball off Kamara's toes as he lined up a shot on goal.
But Albion came under pressure again just before the hour mark when Harley's pinpoint centre picked out Elliott, whose close-range header lacked the accuracy to beat Kiely.
And Kiely pulled off a wonder save in the 64th minute when he beat out Caldwell's point-blank header from Elliott's right-wing corner.
Mowbray made a change seconds later as Ellington made way for ex-Claret Richard Chaplow.
Albion continued to battle away against the odds and appeared to have seen off Burnley's threat - before suffering a fatal blow just three minutes from time.
Clarets super-sub McCann kept his nerve to head Duff's right-wing cross into the top left-hand corner.
There was just no time left for weary Albion to fashion an equaliser and they headed back down the M6 empty-handed.
BURNLEY (4-4-2): Jensen; Duff, Thomas, Caldwell, Harley; Elliott (Spicer 79), Djemba-Djemba, O'Connor (McCann 45+4), Jones; Akinbiyi (McVeigh 72), Gray. Subs not used: Coyne (gk), Coughlan.
ALBION (4-4-2): Kiely; Albrechtsen, McShane, Perry, Robinson; Gera, Greening, Koren, Koumas; Ellington (Chaplow 64), Kamara (Phillips 76). Subs not used: Daniels (gk), Hodgkiss, Hartson.
GOALS: BURNLEY - Gray (16, 48), McCann (87). ALBION - Koumas (6), Ellington (7).
BOOKINGS: BURNLEY - Djemba-Djemba (foul 21), Harley (foul 51). ALBION - Kamara (foul 60), Gera (foul 81).
SENDING-OFF: ALBION - McShane (serious foul play 44).
REFEREE: M Jones (Chester).
ATTENDANCE: 12,500.
ALBION STARMAN: Robert Koren.
(PICS BY LAURIE RAMPLING)
