Swindon 1 Brentford 0
Adam Forshaw was sent off as Brentford suffered a setback in their bid to seal automatic promotion.
Forshaw picked up a second yellow card midway through the second half at the County Ground, where Louis Thompson’s goal a minute before the interval was enough to give Swindon victory.
The result leaves the Bees six points behind leaders Wolves, whose promotion was confirmed, but Mark Warburton’s side are seven points clear of Leyton Orient, who moved into third place with a 5-1 win against Gillingham.
Brentford keeper David Button saved Michael Smith’s 13th-minute penalty after Alan McCormack, playing against his former club, had fouled Alex Pritchard in the area.
But Button was unable to rescue his team when Thompson fired home after Jonathan Douglas had given the ball away.
The goal came after a spell in which Brentford were on top, with Marcello Trotta missing a good chance to put them ahead after being found by Clayton Donaldson’s cross.
Substitute George Saville had an effort well saved by Robins keeper Wes Foderingham, but otherwise the visitors struggled to create clear-cut chances, especially after the influential Forshaw was dismissed following a challenge on Rafael Rossi Branco.
James Tarkowski did have an opportunity to equalise with nine minutes remaining but the defender scuffed his shot wide.
Brentford: Button, McCormack, Tarkowski, Craig, Bidwell (Grigg 87), Forshaw, Douglas, Diagouraga (Saville 56), Donaldson, Trotta (Dallas 66), Judge.
Subs not used: Lee, Dean, Reeves, Yennaris.