NatWest Pro40 D2, Worcester: Surrey 220-6 (40 overs) beat
Worcestershire 207-9 (40 overs) by 13 runs
Worcestershire missed a chance to secure automatic promotion, while Surrey kept their Pro40 Division Two title hopes alive with a 13-run win.
Chasing 221 for victory, the Royals looked well-set at 179-3 before losing six wickets for 15 runs.
Chris Schofield took 3-34, including Ben Smith caught at deep backward square for 76, and Nayan Doshi 2-33.
Surrey captain Mark Butcher provided the foundation with 79 from 101 balls as the Brown Caps posted 220-6.
Surrey can take the title on Sunday if they beat Somerset while Gloucestershire lose to Kent.
If Surrey lose at Taunton they will face a promotion playoff against the side third-from-bottom in Division One, with Worcestershire promoted.
Otherwise, the Royals will have to take part in the final match on 24 September.