Brentford were left to rue missed chances as Darren Bent rescued an undeserved point for Derby.
The Bees had led through Alex Pritchard's sensational goal midway through the first half and Mark Warburton's side were dominating play.
Jonathan Douglas had a shot cleared off the line, while Andre Gray, on another day would have had a hat-trick.
But Derby hit back in stoppage time as Jeff Hendrick's shot somehow found Darren Bent and he was on hand to fire home.
Conceding so late was a matter of great frustration to the squad and they exchanged some harsh words in the dressing room, Warburton admitted.
Pritchard, on the other hand, dismissed it as part and parcel of football and is keen to put things right at Sheffield Wednesday tomorrow.