There was never much between the sides at Prenton Park but certainly the Merseysiders created the better opportunities and deserved the points.
Craig Curran fired wide early on for Rovers before the same player then brought an excellent save from Wojciech Szczesny who later did well to smother out a close-range effort by Terry Gornell.
Leon Legge missed the target with a third minute header for Brentford and was only inches wide with a 25-yard free-kick approaching the half-hour.
Both sides produced some lively approach work without the end product before Tranmere broke the deadlock on the hour from a rehearsed move. A clever John Welsh free-kick split the Bees rearguard and Curran raced clear to put an angled shot past the keeper.
Gornell missed a great chance to double the margin six minutes later when he fired across the face of the goal from close range.