Barnstaple ran away with the game in the second half to defeat Brixham 48-15 at Astley Park.
Barum were only 15-3 up at half time, which is no mean feat at a traditionally tough place to win as a visitor.
After the interval it was largely one-way traffic as Barum ran in five tries to a couple in reply.
Winston James, the Barnstaple captain, said it was a memorable win in some ways and workmanlike in others.
"I cannot remember ever going to Brixham and winning by such a wide margin," said James.
"There was no secret to it, other than we played well for long periods of the game.
"Our set piece was solid and we made sure we did not lose the ball when we had it.
"Brixham scored two tries - one gifted, the other fully deserved - but generally we defended well in the backs and stopped them getting going.
"Considering we had mostly wingers in the backs filling in as Jake Murphy and Ryan Carter were unavailable, our defence was superb.
"When Brixham had us under pressure near our own five-metre line we not only held them out but turned defence into attack."
James, who bagged a try hat-trick in last Saturday's win over Bracknell, scored once against Brixham and dropped the ball when it looked easier to dot it down for a second.
Other try scorers were Dylan Gosling, Will Topps (2), Ben Hilton, Josh Davies, Brendan Darley and George Snell. Haydn Lidstone kicked four conversion.