Three penalties from new recruit Matt Down and second-half tries by Winston James and Luke Berry took Barnstaple to a 19-7 win over Amersham and Chiltern.
It was a second home win for Barum in the new National League Three South West season but came with a much less impressive performance than in the opening-day victory against Redingensians.
But at the end of a scrappy clash in which both sides were far from clinical when near the try line, Barnstaple deserved their win.
While the home side were looking to bounce back from last week's defeat at Weston-super-Mare, Chiltern arrived with two bonus-point home wins behind them.
Barnstaple had to make changes to their side, most notably at fly half where head coach Steve Perry was ruled out by injury and Ryan Carter stepped up from inside centre to wear the No 10 shirt.
Despite the disruption, they dominated the opening 10 minutes but were unable to turn their pressure into points and lost Linford Brock to an injury he suffered in making a line-breaking run in only the first minute.
Down, his replacement at outside centre, had travelled down from Nottingham to take a place on the bench alongside his brother Jon. He kicked two penalties in two minutes to put Barnstaple 6-0 up at half time and added a third 10 minutes into the second half which showed the value of a steady kicker as it came amid a run of four misses by three Chiltern players.
The game looked up for the visitors in the 67th minute after James's try. There was a case for Barnstaple being awarded a penalty try as Rhys Keith was sin-binned for pulling down a maul on the line. It made little difference, though, as James was driven over by his team from the next play.
A dramatic final act began when Jon Down was yellow-carded for putting his hands into a ruck on 73 minutes. Chiltern kicked the penalty to touch, drove from the lineout and then saw fly half Ross Bugden stepped through to score under the posts and add the conversion.
With Keith returning to the field, Chiltern now had the one-man advantage – but it was Barnstaple who scored next. Fluent backs moves had been few and far between but they strung one together from a scrum, sweeping from left to right across the 22 for full back Berry to score in the corner. It was an attractive try to win a match that finished in ugly fashion.
Barnstaple lock Tom Skelding and opposite number Jono Bradbury were sin-binned for fighting and referee Carl Bennett showed James the yellow card too. The Barum captain felt aggrieved after others involved escaped unpunished but was foolish to get involved in a another dust-up with an opponent off the field from which he had to be pulled away by coach Steve Perry.