A tough night at Oakwell, as Brentford came away with the points.
Ivan Toney proved the difference, netting midway through the second half, leaving the Reds 14th in the Sky Bet Championship with 16 points from 13 games.
Valérien Ismaël will be looking to get back to winning ways on Saturday, as Barnsley travel to Blackburn for a 3pm kick-off.