A maiden one-day cup century from Victorian Travis Dean was unable to prevent South Australia collecting an 11-run win and move a step closer to a berth in next week's finals.
Chasing South Australia's imposing tally of 6-356, the Vics stayed in the hunt thanks to Dean's 119 off just 98 balls at North Sydney Oval.
Victoria were without big-hitting Cameron White due to injury, but rookie opener Matt Short helped get the Bushrangers off to a bright start with 81 (off 83).
However, the dismissal of Australian representative Peter Handscomb for 21 at 3-203 left the Bushrangers with too much to do as the run-rate mounted.
Some late lusty hitting from the tail-end meant Victoria needed 23 from the final over, eventually finishing on 8-345.
South Australia dominated the Victorian bowlers from the outset of their innings, with Jake Weatherald (71) and Alex Carey (33) putting on a run-a-ball 107 for the opening wicket.
But it was a dynamic cameo from No.6 Jake Lehmann - 63 not out off just 25 balls - which proved the difference in the final wash-up.
The penultimate-round win helps South Australia jump into second spot in the standings, though having played a match extra than their rivals.
Victoria: Marcus Harris, Matt Short, Travis Dean, Peter Handscomb (c, wk), Sebastian Gotch, Blake Thomson, Will Sutherland, Peter Siddle, Chris Tremain, Scott Boland, Fawad Ahmed. Sam Harper 12th.
South Australia: Alex Carey (wk), Jake Weatherald, Callum Ferguson (c), Tom Cooper, Alex Ross, Jake Lehmann, Cam Valente, Michael Cormack, Daniel Worrall, Chadd Sayers, Spencer Johnson. Kelvin Smith 12th.