Keith Andrews felt Brentford deserved at least a point from their trip to Sunderland.
Wilson Isidor’s header in the sixth minute of stoppage time secured adramatic win for the home side.
Igor Thiago’s third goal of the season put the Bees ahead on 77 minutes, but Enzo Le Fee equalised with a penalty, before the home side snatched the points.
“Bitterly disappointing; the nature of it, the timing,” said Andrews.
“Probably not a fair result, but football sometimes isn’t fair. I’m just disappointed we didn’t manage the last few minutes a bit better.
“We’re just disappointed with how we didn’t manage those few key moments.”
It was a hugely frustrating day for Brentford, who had a goal disallowed in the 21st minute.
Dango Ouattara netted after being set up by Nathan Collins’ pass, but the goal was ruled out following a VAR check for offside.
And in the second half, Kevin Schade’s penalty was saved by keeper Robin Roefs after Collins had been fouled by Reinildo Mandava.
Brentford eventually broke the deadlock when Thiago’s header from Frank Onyeka’s cross bounced in off the underside of the crossbar.
But Sunderland levelled when Le Fee converted the spot-kick after Rico Henry had fouled Habib Diarra, before Isidor headed in Granit Xhaka’s cross.
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