SUBSTITUTIONpublished at 21:24 British Summer Time 8 May 2015
Brentford make a change, bringing Stuart Dallas on for midfielder Jota. What can Dallas offer as Brentford push for a winner?
Amorebieta scores late winner for Boro
Jelle Vossen header put Boro ahead
Andre Gray levelled after Konstantopoulos error
Second leg on 15 May
Phil Harlow
Brentford make a change, bringing Stuart Dallas on for midfielder Jota. What can Dallas offer as Brentford push for a winner?
New arrival Fernando Amorebieta concedes a free-kick for a clear foul on Alex Pritchard just outside the box, getting a yellow card in the process just moments after coming on for Boro. You suspect that wasn't what was whispered in his ear just before coming on...
Grant Leadbitter has the chance to curl in a free-kick from out on the left but his effort is to close to Brentford goalkeeper David Button, who collects into his midriff.
Shortly after and we have our first change as Lee Tomlin, who has been on a yellow card since early in the first half, is replaced by Fernando Amorebieta for Boro.
John Dykes: When you miss a sitter, you put your everything into making up for it! Great tenacity from Gray to earn the equaliser.
Daniel Woodley: Once again the Championship doesn't disappoint! Can't take my eyes off this game.
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Brentford are getting Spanish midfielder Jota on the ball more and more and he is making things tick in the middle. Boro's intensity has dropped from the stellar level of the first half and Brentford are enjoying the extra split-second on the ball.
Middlesbrough goalkeeper Dimi Konstantopoulos has to re-tie his bootlaces, taking off his gloves to do so. He is very meticulous about the whole thing. Brentford fans urge him to get a bit of a move on...
Another magnificent save in a match that has been full of them, with Dimi Konstantopoulos arcing his back to get a hand to a looping, back-where-it-came-from header from Brentford's Jonathan Douglas. This is some match.
Whatever happened to the cagey, safety-first play-off football we might have expected?
This is end-to-end with both teams going for the win, tackles flying in and chances coming for both sides. Has anyone told them they've got another chance next week?
Ian Holloway
Ex-Blackpool and Crystal Palace manager, BBC Radio 5 live
"What a save from Button. He flicked it over the defender and volleyed with his left foot. I thought it was in for a second, but what a save.
"It's so finely balanced now. This is anybody's game."
That is one of the saves of the season! Brentford's David Button produces an amazing piece of athleticism, leaping into the air and just getting a palm to a fierce Albert Adomah effort which had been destined for the top corner. Boro must have thought they were about to go back ahead there.
Griffin Park is absolutely jumping now. A fine Harlee Dean tackle in the box - with zero margin for error - wins Middlesbrough a corner but the resulting header is straight at David Button.
Ian Holloway
Ex-Blackpool and Crystal Palace manager, BBC Radio 5 live
"The ball's played over the top, Gray's chased a lost cause and he was so alert to roll it into an empty net.
"That's a calamity out of nothing, but it's exactly what the game needed. The centre-half should have dealt with it. He could have cleared it out, and if that had been the case, it would be a throw-in now.
"It's buzzing here at Brentford."
We criticised him a moment ago, but it's brilliant work from Andre Gray as he capitalises on a Dimi Konstantopoulos error to equalise.
An optimistic ball over the top should have been belted into the stands by the Boro keeper but he dithers slightly and allows Gray to nip the ball off his toes just outside the box before turning 180 degrees and rolling the ball into the net from an angle.
Ian Holloway
Ex-Blackpool and Crystal Palace manager, BBC Radio 5 live
"What a chance. Odubajo put a great low cross in, in between the two centre-backs, and Andre Gray has been banging those in all season. It's a terrible miss for the boy. Brentford really needed that."
Horrible miss from Brentford striker Andre Gray, who just hasn't got going tonight. The ball breaks to him inside the six-yard box after Jota flicks it on and with just the keeper to beat he fires over on the half volley. Will Brentford get a better chance to equalise?
Middlesbrough's on-loan striker Patrick Bamford shows a touch of Premier League class as he brings the ball down and pushes it past James Tarkowski, who clatters into him to earn a yellow card seconds after the restart.
Industrial, agricultural, a reducer: take your pick of euphemisms for that challenge...
Rob Stevens
BBC Sport at Griffin Park
"Brentford were subdued after Jelle Vossen gave Boro the lead midway through the first half. Bees striker Andre Gray has hardly been in the game but Alan Judge has been a bright spark for the home side.
"Mark Warburton will want more artistry from his playmaker in the second half. Middlesbrough boss Aitor Karanka may be sweating later on as four of his players are on yellow cards - a sending-off would be costly."
The managers have made their stroll across the pitch to the dug-outs, the players are ready and Middlesbrough get the second half under way. No changes for either side at the break.
Ian Holloway
Ex-Blackpool and Crystal Palace manager, BBC Radio 5 live
"The next goal is absolutely vital. If Middlesbrough can get it, it will make it almost impossible for the mindset of Brentford to get over the fact that they've already been beaten twice by them."
Live commentary continues on BBC Radio 5 live via the Live Coverage tab.
So Jelle Vossen's header is the difference at half-time. Can Brentford pull it back after the break?