Julien Vetro scored his first Clarets goal but a second-half comeback earned Brentford U21s a 2-1 victory on Friday afternoon.
Burnley goalkeeper Jon Ander Vilar Robinson saved a late penalty too on an eventful but ultimately frustrating day at Turf Moor.
There were four changes to the side that started Monday’s night’s defeat at Swansea City and two came in defence, with Alex Healy-Byrne starting at right-back and Noah Adekoya at centre-back.
Aaron Ramsey made a second appearance for the U21s on his return from a serious knee injury, with Mike Tresor featuring for the first time since January’s Emirates FA Cup victory at Reading.
Both teams took time to weigh each other up in the early stages of a sunny day in BB10, with Ramsey pulling the first shot of note narrowly wide in the 12th minute.
The visitors had a spell of possession but were unable to work Vilar Robinson in the Burnley goal before the Clarets broke the deadlock with a fine team move in the 27th minute.
Vilar Robinson picked out Bauress, who spread the ball wide left for Tresor. The winger then squared perfectly for Vetro to score his first Burnley goal.
The majority of the remaining 15 or so first-half minutes were played in the middle of the pitch, with both teams working attacks but no shots.
That was until the 43rd minute, when second-year scholar Adekoya produced a strong block off the line to deny Iwan Morgan an equaliser.
In a quick start to the second half Adekoya produced another important block that allowed Tresor to get a shot away within a minute of the restart, but his effort went wide.
Vilar Robinson then made a reaction save low to his right to thwart Romelle Donovan, before two Brentford goals in seven minutes swung the momentum in their favour.
Both came from Isaac Holland, who pounced on a moment of hesitation at the back to latch onto a long ball and slot home the equaliser low.
Clarets Manager Andy Farrell then turned to his bench for the first time on the hour, introducing Hamzat Balogun and Basilio Socoliche in place of Oli Pimlott and Kamarni Ryan.
Holland made it 2-1 to the visitors just three minutes later though, capitalising on a good first touch to finish powerfully into the bottom left corner.
With the game meandering Farrell made two more planned changes 15 minutes from time, replacing Ramsey and Tresor with Charlie Veevers and Tom Tweedy respectively.
McDermott later made way for Brandon Ly before Vilar Robinson kept his team in the match with an 84th-minute penalty save.
After Balogun fouled in the area Holland had the opportunity to complete his hat-trick, but the ‘keeper made a big save low to his right.
Adekoya came closest to earning Burnley a point with a stoppage-time header, but Brentford’s defence held firm for the win.
Farrell’s side stay 3rd in the Professional Development League North table with 44 points from 26 matches, ahead of a Premier League Cup quarter-final against Chelsea on Monday night.
Kick-off at the Grant Store Victory Park Stadium in Chorley is 7pm, and Burnley season ticket holders can watch for free by presenting their card at the turnstiles.
Burnley: Vilar Robinson, Healy-Byrne, Pimlott (Balogun 60), Ashton, Adekoya, Bauress, Vetro, Ramsey (Veevers 75), Ryan (Socoliche 60), McDermott (Ly 81), Tresor (Tweedy 75)
Brentford: Rose, Holland (Grey 90+2), Williams (Dickov 46), Stephenson, Arthur, McManus, Krauhaus, Brierley, Morgan, Owen, Donovan
Unused Substitutes: Wilcox, Avenell, Peters
Goals: Vetro 27’, Holland 56’, 63’