Oxfordshire opened up a 30-point lead at the head of the Western Division table after reeling off a third successive win in The Parks.
Seam bowling of the highest order from Stewart Laudat, who returned career best figures of seven for 38, and Keith Arnold, who weighed in with three for 29, saw Cornwall collapse to 75 all out in their second innings.
The men from the Duchy were 28 for six at one stage as Arnold and Laudat bowled unchanged through 29.2 overs, but Neil Williams summoned up some late resistance with 30 not out. Left with just 79 to win, Oxfordshire got home by six wickets, with Charlie Knightley hitting an unbeaten 25.
In the Eastern Division, the weather was the only winner at Saffron Walden with day two of the Cambridgeshire v. Cumberland fixture washed out by rain. The five points gained by Cumberland stretched their lead at the top of the division to 36 points, but second-placed Buckinghamshire have three matches in hand.
The Parks: Cornwall 185 & 75 (SV Laudat 7-38) Oxon 182-8 & 80-4 Oxon (22) beat Cornwall (3) by 6 wickets
Saffron Walden: Cambs 168 (RJ Rollins 52) Cumberland 136-9 (A Akhtar 5-19). No play on day two - rain. Drawn. Cambs 5 Cumberland 5