Chasing Western Fury’s formidable total of 4/323, Wellington’s 116 off 125 balls and a 117-run sixth wicket partnership with hard-hitting debutante Tabatha Saville (53) took the Scorpions within striking distance late in the day at Adelaide Oval No. 2.
However, the last four wickets fell quickly in the late chase for runs, with SA dismissed for 302 in the 49th over.
Earlier, WA captain Villani won the toss and elected to bat.
It was leg-spinner Wellington who made the first breakthrough for SA in the 12th over, dismissing Chloe Piparo for 25.
However, this allowed experienced duo Nicole Bolton (125 not out) and Villani (139) to create a rock-solid platform for the Fury, adding 204 runs for the second wicket.
Medium-pace bowler Samantha Betts took the scalps of Villani and Amy Jones, while some sharp fielding from Katelyn Pope removed Heather Graham for just one run.
SA openers Bridget Patterson and Tegan McPharlin were dismissed early before Tahlia McGrath (20), Sophie Devine (38) and then new Scorpion Ashleigh Gardner (34) started to score freely.
Coming in at number five, it was Wellington who did the most damage with the bat, producing an incredible innings exactly when it was needed for her side.
Her previous highest one-day score was 37.
SA will face Tasmania at Adelaide Oval No. 2 on Sunday 8 October from 10am.