BARNSTAPLE did enough in the first half to earn a bonus-point win over Malvern.
They dominated before the break and scored 29 unanswered points.
But after a poor second-half display, in which they scored one try to the visitors' three, Barum had to settle for a 36-19 victory.
Josh Squire set up tries for Will Topps and Ben Vellacott, as well as kicking a penalty and conversion, before departing with a potentially serious injury to his left knee on 24 minutes.
Linford Brock crossed on the right touchline for a 35th-minute try, superbly converted by Topps.
Brock then set up full back Topps for his second try, which he also converted, in injury time.
Barnstaple switched off at the start of the second half and Tom Longley strolled through for two tries that he also converted.
The home side stretched their lead again in the 56th minute when Winston James forced his way over and Topps converted. But the match finished with James in the sin bin and Malvern on the front foot, with a spell of pressure leading to a try from the final play by James Southall.
A shock 14-5 home win for Bude over St Austell, the Tribute Western Counties (west) leaders, allowed second-placed Bideford to close the gap to five points with a 39-12 win over Tavistock at King George's Field.
Bideford, like Barnstaple, did most of their work in the first half with tries by Dave Slee, Andrew Loosemore, Harvey Brown and Stefan James who added three conversions and two penalties.
Tavistock replied with two tries in the second half, while Matt Dennis added Bideford's fifth try, converted by James.
South Molton won 20-11 at home to Dartmouth in Devon One, while Ilfracombe lost their Devon Two match at North Tawton 20-7.