Oxfordshire went down to Worcestershire by two wickets in a low-scoring encounter at Hagley Hall on Wednesday.
Oxon need to beat Shropshire next week to make sure of qualifying for the knock-out stages.
After choosing to bat first, the visitors slumped to 83-9 before a last-wicket stand of 61 between Neil Megson and Ian Curtis helped them to 144-9, Megson finishing with 50 not out.
That total looked enough when Worcestershire collapsed to 85-7 against Curtis and Darryl Woods.
However, Gary Mills hit an unbeaten 44 to see them home by two wickets with an over to spare.
Latest Sport news
- Liam Sercombe – changing roles is part of Oxford United adapting to life at the higher level
- Michael Appleton: Oxford United must improve against League One's route one merchants
- Millwall result will determine Oxford United mood for next fortnight, says captain John Lundstram
- Oxford United boss issues warning over dangerous Millwall strikers
- Millwall manager Neil Harris full of respect for 'attack-minded' Oxford United
- Striker Wes Thomas’s calf injuries proving a mystery for Oxford United
- OxVox column: How I ended up building a network of exiles
- FOOTBALL: Justin Merritt backs Oxford City to deliver without suspended captain Scott Davies
- RUGBY UNION: Oxford Harlequins and Banbury ready to lock horns in South West 1 East
- FOOTBALL: Wantage Town eye good end to tough week ahead of FA Trophy tie at Weymouth