South Australia 166 (Drew 49, Scott 46, Jackson 6-31) beat Western Australia (Turner 53, Whiteman 48, McAndrew 5-40) by two runs
Western Australia have suffered an almighty collapse of 7 for 31 against South Australia, sparked by Nathan McAndrew's five-wicket haul, to eventually lose by two runs and remain winless in the One-Day Cup after two games.
Two days after being upset by New South Wales, Western Australia looked set for victory at 133 for 3 in pursuit of South Australia's 166 at Sydney's Cricket Central.
But the three-time defending champions fell apart miserably, with McAndrew claiming career-best List A figures of 5 for 40 as Western Australia were all out for 164 in the 38th over.
The loss leaves Western Australia with their worst start to a season since 2015, and the first time they have suffered back-to-back 50-over defeats in nine years.
The defeat came despite the best efforts of quick Bryce Jackson, who claimed 6 for 31 and the best figures for Western Australia in the competition's history.
Jackson has long been touted as a potential talent in Western Australia, but a series of major back injuries denied him a debut until age 24 last summer.
The right-arm quick took 3 for 67 in his maiden match against Tasmania in February, before taking his chance on Tuesday with Jhye Richardson rested.
He had Henry Hunt caught behind with a ball that swung away in his first over, before getting Mackenzie Harvey and Daniel Drew in his next over.
And after Liam Scott (46) and Daniel Drew (49) steadied the ship for South Australia, Jackson returned to get rid of both of them before beating McAndrew for pace on the hook shot.
While Western Australia wobbled early in their chase, the competition heavyweights appeared to have the match under their control.
With Ashton Turner going after Henry Thornton by cutting him for six and taking 16 off another over, a bonus-point win looked the most likely scenario.
But the match swung viciously after Sam Whiteman pulled Wes Agar down the throat of Thomas Kelly at deep square leg on 48.
Ashton Agar and Baxter Holt followed in similar fashion to McAndrew as the West Australians lost all control of the match.
And when McAndrew had Matthew Kelly caught behind and clean bowled AJ Tye for a duck in his next over, Western Australia still required 10 for victory.
Ben Manenti then landed the killer blow when he nicked off Turner on 53, leaving Lance Morris and Jackson six runs to get for the final wicket.
Jackson was ultimately stumped trying to drive Manenti, denying him a dream day and handing South Australia their first win over Western Australia since 2017.
