Substitute Fernando Amorebieta scored a dramatic late winner to give Middlesbrough victory in their play-off semi-final first leg at Brentford.
The Venezuelan defender, on loan from Brentford’s west London rivals Fulham, lashed home in stoppage time with the aid of a deflection to give Boro a precious advantage.
Andre Gray had earlier capitalised on a blunder by Boro goalkeeper Dimi Konstantopoulos to cancel out Jelle Vossen’s first-half header.
The clash was outgoing Bees manager Mark Warburton’s final game at Griffin Park, and his dream of signing off at Wembley is now hanging by a thread.
Boro head coach Aitor Karanka took his players to Marbella this week to prepare.
They still looked in holiday mode in the opening stages, allowing Alan Judge room to whip in a fierce shot which Konstantopoulos tipped onto a post at full stretch.
But the visitors took the lead after 25 minutes. Vossen slipped unnoticed between two Brentford defenders to meet Adam Clayton’s cross and guided his header across David Button and into the corner of the net.
Button then kept his side in the tie with two fine saves in the space of a minute. First he got down well to turn wide Lee Tomlin’s low drive at the near post, and from the corner somehow clawed out Vossen’s close-range effort.
Boro’s physical approach earned them four bookings in the first half and following one foul on Judge, Brentford went close to an equaliser, but James Tarkowski nodded Alex Pritchard’s free-kick narrowly over.
Gray missed a golden opportunity to equalise shortly after the interval when he blazed over after Jota had flicked on Judge’s cross.
But the striker made amends in the 54th minute when he chased what looked like a lost cause from Jake Bidwell’s hopeful ball into the channel.
Konstantopoulos came to meet the ball on the corner of the area, but Gray charged down the goalkeeper’s clearance before spinning around and slotting the ball into an empty net.
Button was called into action again on the hour mark with another fine save, diving to his left to palm Albert Adomah’s piledriver over the crossbar.
Konstantopoulos went some way to redeeming himself moments later when he pushed over Jonathan Douglas’s looping header,
Amorebieta then stunned Griffin Park in the third minute of stoppage time. George Friend headed down Grant Leadbitter’s corner and the full-back’s shot clipped Bidwell and flew into the net.
Brentford: Button, Odubajo, Dean, Tarkowski, Bidwell, Diagouraga, Douglas, Jota (Dallas 77), Judge (Smith 88), Pritchard, Gray. Unused substitutes: Macleod, Craig, McCormack, Bonham, oral.
Middlesbrough: Konstantopoulos, Whitehead, Ayala, Gibson, Friend, Clayton, Leadbitter, Adomah, Vossen (Forshaw 83), Tomlin (Amorebieta 73), Bamford (Garcia 90). Unused substitutes: Ripley, Reach, Omeruo, Nsue.
Referee: Jonathan Moss (W Yorkshire).