Brentford were made to work hard to book their place in the third round of the EFL Cup by Forest Green Rovers
The League Two outfit took the lead in only the eighth minute when Jack Aitchison fired home after a stubborn run from Nicky Cadden.
But Yoane Wissa hauled the Premier League side level on the hour mark with a composed finish from 20 yards.
Bryan Mbeumo then made it 2-1 before the visitors had Ebou Adams sent-off. The one-man deficit saw Rovers toil in the final few minutes and Marcus Forss got a third with only four minutes to go.