Cumnor lost ground in the title race when they failed to take the final Oxford 2nd wicket – despite bowling 12 overs at the last pair.
Hosts Cumnor started slowly after being asked to bat before Adam Cook (61) and Sam Jones (62) injected some urgency to take them to 213-7.
Todd Hutcheson (62) put the visitors ahead of the required rate, but wickets then tumbled and it was left to tailenders Philip Evans and Zia Hamid to secure the draw on 187-9.
Cumnor 15pts, Oxford 2nd 9.
Horspath could still win their first title after they secured a six-wicket win at Oxford Downs, who are not yet safe from the drop.
Only Tom Norris (40) put up much of a show in Downs' innings, which closed on 169-7.
Alister Gibbins took 3-43 for Horspath and then watched Ned Murray hit 46 and Robbie Eason close out victory with an unbeaten 61.
Oxford Downs 6, Horspath 25.
Banbury Twenty's survival hopes were dealt a blow when they went down to Shipton-under-Wychwood – one of only two sides they can realistically hope to catch.
Twenty won the toss, but not much else went their way as Shipton racked up 271-6 thanks to Andrew Hemming (77), Tim Senior (54) and Jason Hunt (50).
Mark Haupt then hit 125 in a bid to keep side in the game, but spinners Paul Hemming (6-40) and Shaun Miller (3-93) combined to dismiss them for 228.
Shipton 25, Banbury XX 7.
Bletchley Town were bundled out for a paltry 80 as Buckingham Town kept alive their hopes of winning their second title in three years.
James Sprittles (5-34) had the visitors in trouble on 68-6, but Ben Stafford blasted 88 not out to take them to 159.
Jason Ell then took 6-17 as the hosts slumped to 46-8 and eventually 80 all out.
Bletchley Tn 5, Buckingham Tn 25.
Bicester & North Oxford endured another dismal day, their latest defeat coming at the hands of leaders Dinton.
Nick Moorman hit 55 for Bicester but, with Tim Brooker taking 4-46, the visitors were restricted to 161 all out.
The loss of three early wickets only delayed the inevitable, as Adam Mould (57no) and Ashley Smith (40no) saw the home side extend their lead at the top.
Dinton 25, Bicester & NO 5.