Barum’s 4-0 defeat to Didcot saw them brought down to earth with an almighty bump at Mill Road following Monday’s valuable win at Mangotsfield United.
The damage was done in the first 25 minutes, with the hosts staring down a 3-0 deficit at the end of it.
A quality header from George Jeacock inside two minutes got the visitors on their way. Sam Barder added another eight minutes later before Morgan Williams headed in the third.
Louis Joyce struck early in the second half to quickly dispel any chances of a second half fight-back.
The defeat, paired with an incredible win for Shortwood United at AFC Totton, means Barum drop down to 18th in League South West with five games left of the campaign.
After Monday’s win, co-manager Kevin Darch admitted the game could have been over after half an hour had it not been for some stand-out goalkeeping. Five days later and Barnstaple quickly fell short of repeating that feat.
The visitors were a goal to the good after 90 seconds when Jeacock got in front of George Nancekivell to flick Williams’ corner past Rob Holmes at the near post.
Barder had extended the lead for the visitors eight minutes later, getting in behind the Barum defence and finding enough room to slip the ball past Holmes and into the bottom corner.
After scoring the first, Jeacock was the provider for the third on 25 minutes, poking the ball past Jordan Walton and sending a cross to the back post for Williams to head home. Game over for Barum.
The hosts had a couple of half chances as the first half neared its end, the best of which falling to George Nancekivell, who headed a Walton corner just wide of the far post.
Had Barum scored early in the second half it may well have reignited the game, but instead it the visitors who struck after four minutes, putting any thoughts of a potential comeback to bed.
Ollie Williams’ cross-cum-shot forced Holmes to get down low and save, but the goalkeeper could only parry it out to Joyce, who managed to find room to poke past the Barum goalkeeper and Tony Radford after they blocked his first effort.
Harry Stevens was brought on midway through the half to make his first appearance since limping off against Bishops Cleeve in February, and it sparked more life into the hosts.
The striker combined well with Hopcroft, who had something of a thankless task in the first half, but had two great chances either side of his strike partner’s introduction to get a goal.
Stevens flicked on for Hopcroft to leave him one-on-one with Leigh Bedwell, but the goalkeeper saved low to his left to deny the striker’s effort. Hopcroft had hit the bar 10 minutes earlier after forcing his way to the edge of the box and letting go of a shot.
Barnstaple Town: Holmes, Radford, Walton (Darragh 61), Heeney, Cooper, Booth, Nancekivell, Gray, Mitchell (H Hopcroft 75), B Hopcroft, Reay (Stevens 67). Subs not used: Knight, Darch.
Didcot Town: Bedwell, Jeacock, Woodley, Hayden, Cattell, McNeill, Agyakwa (Reid 69), Barder, Joyce, Thomas (Humphries 65), Williams. Subs not used: Ballard, Lovegrove.