Great & Little Tew and Challow & Childrey will meet on Saturday with the losers likely to miss out on a promotion place from Division 2 after both failed to win at the weekend.
Bourton Vale’s home victory over Tew took them back to the head of the table, and they will finish top if they win at already-relegated Hanborough this week.
Vale were asked to bat and responded by scoring 218-6 dec from 50 overs, with Alex Fateh hitting 107 and Charlie Garratt 41.
Tew were never in the hunt despite Anthony Smith’s 62 and they were all out for 144.
Bourton Vale 25pts, Gt & L Tew 4
Challow & Childrey never recovered from a poor start at home to Oxford & Bletchingdon Nondescripts.
Nondies openers Tim Rattigan (63) and Jeremy Liddy – who finished 141 not out – added 150 for the first wicket as the visitors raced to 269-3.
Ben Jones (70) and Olly Dimbylow (48) gave Challow hope, but Mark Strong (pictured) took 5-60 and the hosts were left to hang on at 224-8.
Challow 8, Nondies 16
Hanborough’s relegation was confirmed when they lost by nine wickets at Long Marston, the only team they could have caught going into the weekend.
Paul O'Reilly took 4-28 as the visitors slumped to 88 all out, then Adam Wells (45) and Mike Lyons (44no) took Marston to 89-1.
Long Marston 25, Hanborough 1
Sandford St Martin could still join Hanborough in Division 3 – but only if Thame Town are relegated from the Home Counties Premier League, Long Marston win at Tiddington and they fail to beat Abingdon Vale.
Tiddington are safe after they beat Sandford by seven wickets.
Chris Thompson (87) led a recovery that saw Sandford reach 192-9, but the visitors always looked like winning while Will Cooper (77no) was at the crease, and victory was assured when Jon Talbot hit an unbeaten 44.
Sandford St Mart 6, Tiddington 25
Dan King’s cultured 125 set Abingdon Vale on their way to a 55-run win at Banbury 2nd and so end their hosts' promotion chances.
Vale finished on 199-9 as Josh Hill (4-67) and Jamil Faruq (3-40) kept it tight.
Banbury then fell apart after tea and were bowled out for 145.
Banbury 2nd 6, Abingdon Vale 25