Western Australia 282 for 6 (Whiteman 137*, Bancroft 51, Pope 3-59) beat South Australia 279 for 7 (Drew 84, McSweeney 53, Short 1-27) by four wickets
Fast bowler Jhye Richardson recovered from a torrid start to complete a successful return from injury before stand-in captain Sam Whiteman's first List A century guided Western Australia past South Australia in the Marsh Cup.
Chasing 280 on a batting-friendly WACA surface, WA started shakily at 27 for 2 after losing openers Josh Philippe and Cooper Connolly to seamer Liam Scott. But their Shield openers Whiteman and Cameron Bancroft steadied the ship by playing calmly in a 96-run partnership.
Coming off a rare subpar Shield match, Bancroft was reprieved on 10 when Daniel Drew dropped a sitter at first slip off Jordan Buckingham. He looked immovable from there and cruised to his half-century before falling lbw to legspinner Lloyd Pope shortly after.
Pope then removed Hilton Cartwright, but Whiteman played fluently and reached 99 with a huge six onto the famous grassbanks before two balls later clinching his first List A ton in his 61st match.
He hit the winning boundary with three balls remaining and was supported at the death by big-hitting Richardson, who smashed 25 off 16 balls. Richardson, who has played three Tests in an injury-plagued career, earlier took 1 for 63 from 10 overs in his second match of the season.
"He's super skillful. He's had a frustrating time, so he's pretty stoked to be playing," Whiteman said of Richardson. "He's also got some runs in him and took pressure off me at the end."
The winless Redbacks were shorthanded after quick Harry Conway was unable to bowl due to a back injury suffered while batting.
Two-time defending champions WA moved to a 4-1 record as they jostle with Victoria at the top of the table.
In warm and sunny conditions, the surface was hard and flat in a notable contrast to the grassy pitch used during last week's low-scoring Sheffield Shield thriller between the teams.
WA decided to bowl and all eyes were on luckless Richardson, who last month returned against Victoria in the Marsh Cup after a long stint on the sidelines following hamstring surgery. But he had another setback after subsequently suffering a dislocated shoulder in a second XI match for WA in Adelaide.
Having made a successful recent comeback in Perth grade cricket, Richardson made a nervous start opening the bowling against aggressive Jake Fraser-McGurk, who last month smashed the world's fastest List A century.
Richardson started with five wides and his mood deteriorated further in his next over when Fraser-McGurk smashed him for two boundaries and two sixes in a 22-run over.
Richardson was reeling after conceding 30 runs in his opening two overs, but Whiteman persisted with him. The gamble appeared to backfire when Fraser-McGurk whacked another boundary before Richardson repaid the faith on the next delivery by getting through his defences with a well-executed slower ball.
After Fraser-McGurk's whirlwind 31 off 15 balls, South Australia batted watchfully and were pinned down in the middle overs by Connolly's accurate offspin. There have been big expectations over allrounder Connolly, 20, who burst into prominence after his heroics in last season's BBL final.
After impressing in WA's opening two Marsh Cup matches, Connolly's hopes of a Sheffield Shield debut were dashed when he suffered a toe injury after an accident on a boat.
Hustling through his deliveries quickly, Connolly dismissed opener Henry Hunt and finished with 1 for 41 from 10 overs.
Half-centuries from Drew and Nathan McSweeney kept South Australia on track for a score over 300. Drew's dismissal in the 33rd over halted their momentum after he fell to debutant left-arm quick Liam Haskett, who performed well in three Sheffield Shield matches this season.
But Scott hit a six off the last ball of the innings and he carried over the momentum with the ball before Whiteman took over in his second match captaining WA's 50-over team.
