Shahbaz Ali and debutant David Smith steered Oxfordshire to a five-wicket win over Cumberland that had looked a tall order.
Oxon only had to chase 236 for victory at Challow & Childrey, which would normally have been routine.
But some ponderous batting and controlled spin bowling from James Lowe and James Beaumont meant the hosts needed 67 to win with just seven overs remaining – despite 61 from Craig Haupt.
Oxon did up the ante, with Smith, who hit 45 off 24 balls, showing great confidence.
Shahbaz accelerated his own innings well to finish unbeaten on 80 off 108 balls.
The key, though, came when Cumberland captain James Smith brought himself on to bowl with Oxon needing 26 runs off three overs.
Smith, who conceded 48 in three overs the previous week, was smashed for 14 in this one, with Oxon's Smith hitting the only six of their innings.
That left Oxon needing a run-a-ball to win, which proved comfortable enough.
Earlier, Gary Pratt had top-scored with 80 for Cumberland after they were put into bat.
A late surge by Graham Dawson (39) and Beaumont (23) gave the visitors hope.
Stuart Hole and Richard Gilbert were economic for Oxon, but Richard Kaufman produced the best figures with 3-41.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here