Barnstaple suffered their heaviest defeat of the season as they were crushed 72-17 by London Irish Wild Geese.
The National Three south west leaders were just too good for their visitors, who have now suffered six successive defeats.
With Old Patesians beating Oxford Harlequins 42-14, Barnstaple have slipped one place to ninth, while London Irish have gone eight points clear at the top.
All Barnstaple's points came in the first half, which finished 32-17 to Irish, with Tom Skelding and Winston James scoring tries and Luke Berry kicking two conversions and a penalty.
Bideford and St Austell will go into next Saturday's top of the table clash in Tribute Western Counties (west) level on 83 points.
Having started today five points clear at the top, Bideford were pegged back this afternoon as they lost 34-19 at Penryn while St Austell were enjoying a 45-3 bonus-point home win against Truro.
It was revenge for Penryn, who lost 70-0 away to Bideford in October, and the second time this season they have had their say in the title race after they beat St Austell in January.
South Molton enjoyed a stunning victory away to Dartmouth in Devon One – thrashing them 100-0 to stay in second place.
Ilfracombe were watched by a crowd of more than 100, including many former players, as they marked the club's 135th anniversary with a 33-14 win over North Tawton.