Burnley’s Premier League survival hangs by a thread after West Ham and referee Jonathan Moss dished out a big dose of capital punishment.
Mark Noble’s early penalty left the Clarets eight points from safety with just three games remaining.
And it was an uphill task for Sean Dyche’s side from the moment Moss controversially sent off Michael Duff for a professional foul on Cheikhou Kouyate that brought about the spot kick.
Replays showed there was cover as the Hammers striker tumbled over Duff’s outstretched leg after just 23 minutes of the game.
But the man in the middle ruled the Clarets defender had denied a goalscoring opportunity and after a brief delay sent Duff for an early bath.
Battling Burnley refused to roll over though and Adrian made fine saves in each half to deny Ashley Barnes and Matt Taylor.
And although Tom Heaton was also in impressive form, it was not enough as another frustrating day in front of goal left the Clarets staring into the abyss.
Dyche made one change, with Barnes returning to the starting line-up following his suspension.
And they survived an early scare when Valencia stole in behind Jason Shackell and just failed to connect from point-blank range from a terrific left wing cross.
But the Clarets settled quickly and in the 14th minute created their first opening. Kieran Trippier clipped a ball into the right side of the box, where Danny Ings flashed a shot across goal and just wide of the far post.
Former Hammer Taylor then delivered an inviting ball from the left that just evade the inrushing Barnes.
And Taylor found an ever better cross moments later to pick out Ings, whose free header from 10 yards agonisingly failed to test Adrian.
But disaster struck midway through the half when Duff controversially saw red after upending Kouyate in the box.
Referee Jon Moss had no hesitation in pointing to the spot, but then stunned everyone inside Upton Park by showing Duff a straight red card.
And Noble compounded the Clarets misery by comfortable slotting home the resulting spot kick.
The reshuffle saw Ben Mee drop into centre back, with Taylor dropping into left back.
And immediately, Stewart Downing looked to expose the left side, taking on Taylor and crossing for Valencia, who was only denied by a magnificent tip over from Tom Heaton.
The Clarets keeper then denied Morgan Amalfitano as West Ham went for the jugular.
But Burnley hung in there and on the half hour Barnes almost conjured up the equaliser with a firm header from a right wing corner that Adrian saved well with his legs.
Half time saw the introduction of Michael Keane for George Boyd, as Dyche reverted to three centre backs, including Jason Shackell and Mee.
And Ings immediately had a wonderful chance to level up the game. The striker’s first touch was fantastic as he controlled a long ball down the line to put himself clear on goal.
And with little support, he opted to go for the near post with an angled effort, but could only find the side netting.
Burnley were now throwing caution to the wind, exposed to the hosts’ breaks. And Valencia somehow missed the target when he was teed-up on the edge of the box.
At the other end, Taylor was superbly denied by Adrian as he threaded a shot through a posse of defenders.
And as the wide open game continued unabated Burnley somehow survived form an almighty scramble after Heaton again saved well from Nolan.
On the hour mark, it was West Ham’s turn to feel aggrieved at referee Moss as Downing hurdled Mee’s challenge in the box and was promptly booked for diving.
And as Burnley became stretched with the one man disadvantage, West Ham began to utilise the space and dominate possession.
But they could not take advantage and put the game to bed as Heaton again saved well from Downing and the impressive Shackell got his head in the way of Kouyate’s piledriver.
BURNLEY: Heaton, Trippier, Duff, Shackell, Mee, Jones, Taylor (Wallace 80), Arfield, Boyd (Keane 46), Barnes (Sordell 79), Ings
Subs: Gilks, KIghtly, Reid, Jutkiewicz
Sent Off: Duff 23
WEST HAM: Adrian, Cresswell, Nolan (Nene 79), Kouyate, Downing, Noble, Jenkinson, Collins, Amalfitano, Valencia (Cole 82), Burke
Subs: Jaaskelainen, Jarvis, O’Brien, Song, Oxford
Booked: Valencia 41, Noble 44, Downing 59
REF: J Moss