Brentford substitute Nicky Forster salvaged a 1-1 with his first touch in a game of two halves with Exeter.
It was a confidence booster for the Bees ahead of Monday night's Johnson's Paint Trophy Southern Final clash between the two sides.
Forster's 94th minute equaliser came when he hammered home after a goalmouth melee to earn the Londoners a deserved point after John O'Flynn had given the Grecians a second minute lead.
He capitalised on a slip by Brentford left-back Craig Woodman to run on and fire an angled drive into the bottom corner.
The first half was all Exeter. Liam Sercombe fired over the angle and Troy Archibald-Henville headed wide when unmarked.
It was a different story after the break, Marcus Bean finding the side netting for the home side as they laid siege to the visitors' goal. When MacDonald side-footed wide from close range late on it looked like a goal would never come - until Forster's late, late strike.