Match ends, Brentford 0, Barnsley 2.
Barnsley pulled off a stunning win to prevent Brentford returning to the Championship summit and end their 21-match unbeaten league run.
Former Tykes defender Ethan Pinnock left Callum Brittain's cross for keeper David Raya, but Conor Chaplin nipped in to turn in the opener and reward the visitors' strong start.
Pinnock then failed to cut out Daryl Dike's low ball across the box and Carlton Morris crashed a shot in off the post.
The Bees, who had not tasted defeat in the league since a 3-2 loss at Stoke on 24 October, struggled to create clear chances throughout, despite late pressure, and were kept scoreless for the first time in 12 matches.
Brentford had seen their automatic promotion hopes ended the last time they hosted Barnsley, who pulled off an unlikely escape from relegation with a 2-1 win on the final day of last season.
The odds of a repeat looked unlikely with the Tykes on a five-match winless league run and facing a Bees side who had won eight out of their last nine, yet they were full value for their half-time lead, with Morris also forcing a decent save from Raya.
The Bees had netted 17 times in four straight league wins, but failed to muster a serious threat until Saman Ghoddos' fierce low drive forced keeper Brad Collins into a good save in first-half stoppage-time.
That was as good as it got for out-of-sorts Brentford, and it was the visitors who went closest to a third goal as Victor Adeboyejo sent a half-volley just wide.
It was a miserable afternoon for Pinnock - who spent two seasons at Barnsley before joining the Bees - and only an offside flag prevented him giving the visitors a third goal when he turned a cross into his own net.
Brentford stayed in second place, a point behind leaders Norwich, while Barnsley climbed to 12th and within seven points of the play-off places.
Reaction - Barnsley 'at their top level'
Brentford head coach Thomas Frank:
"It was inevitable that we would not go the rest of the season unbeaten, but I think we have been so consistent and so good.
"Today there was no lack of effort and they put everything out there. There was big determination and we lost a game to a team that were at their very top level.
"This is going to go to the end of the season, I have no doubt about that, so everyone speaking about promotion must know the only thing we speak about is the next game."
Barnsley boss Valerien Ismael:
"For a few weeks we've performed well but not got the result, but all the time against the top sides like Norwich and Watford we have been very close.
"This win means a lot because we said we needed to make the next step. How good you play is all very well, but in football you need a result.
"Since I have been trainer here it was the best week. We have a way to play football and today was the result of three months' work."
Line-ups
Brentford
Formation 4-3-3
- 1Raya
- 22DalsgaardSubstituted forRasmussenat 74'minutes
- 5Pinnock
- 29Bech Sørensen
- 3Henry
- 14DasilvaSubstituted forJensenat 74'minutes
- 27Janelt
- 20GhoddosSubstituted forForssat 74'minutes
- 19MbeumoSubstituted forFosu-Henryat 64'minutes
- 17ToneyBooked at 90mins
- 7Canós
Substitutes
- 4Goode
- 8Jensen
- 15Forss
- 23Reid
- 24Fosu-Henry
- 28Daniels
- 30Rasmussen
- 31Zamburek
Barnsley
Formation 3-4-3
- 40Collins
- 26SollbauerBooked at 25minsSubstituted forSibbickat 67'minutes
- 30Helik
- 6Andersen
- 7Brittain
- 21PalmerSubstituted forWilliamsat 77'minutes
- 27MowattBooked at 90mins
- 4Styles
- 10DikeBooked at 43minsSubstituted forWoodrowat 56'minutesBooked at 83mins
- 14MorrisSubstituted forAdeboyejoat 56'minutes
- 11ChaplinSubstituted forFrieserat 56'minutes
Substitutes
- 1Walton
- 2Williams
- 8Kane
- 9Woodrow
- 20Sibbick
- 22Oduor
- 28Frieser
- 29Adeboyejo
- 34Moon
- Referee:
- David Coote
Match Stats
- Possession
- Home63%
- Away37%
- Shots
- Home14
- Away11
- Shots on Target
- Home3
- Away6
- Corners
- Home7
- Away5
- Fouls
- Home9
- Away24
Live Text
Post update
Full Time
Second Half ends, Brentford 0, Barnsley 2.
Booking
Ivan Toney (Brentford) is shown the yellow card for a bad foul.
Post update
Foul by Ivan Toney (Brentford).
Post update
Michal Helik (Barnsley) wins a free kick in the defensive half.
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Attempt saved. Alex Mowatt (Barnsley) left footed shot from the left side of the box is saved in the centre of the goal. Assisted by Dominik Frieser.
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Corner, Brentford. Conceded by Michal Helik.
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Mads Bech Sørensen (Brentford) wins a free kick in the defensive half.
Post update
Foul by Dominik Frieser (Barnsley).
Post update
Attempt missed. Ivan Toney (Brentford) header from the centre of the box is too high. Assisted by Mathias Jensen with a cross following a set piece situation.
Booking
Alex Mowatt (Barnsley) is shown the yellow card for a bad foul.
Post update
Ivan Toney (Brentford) wins a free kick on the left wing.
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Foul by Alex Mowatt (Barnsley).
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Foul by Ivan Toney (Brentford).
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Michal Helik (Barnsley) wins a free kick on the right wing.
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Attempt blocked. Alex Mowatt (Barnsley) left footed shot from outside the box is blocked. Assisted by Victor Adeboyejo.
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Hand ball by Cauley Woodrow (Barnsley).
Booking
Cauley Woodrow (Barnsley) is shown the yellow card.
Post update
Vitaly Janelt (Brentford) wins a free kick in the defensive half.
Post update
Foul by Alex Mowatt (Barnsley).