Magellan Ashes hopeful Cameron Bancroft couldn't continue his hot form as a Western Australia batting collapse opened the door for South Australia to snatch an unlikely JLT Sheffield Shield victory.
WA looked to be in complete control after securing a 151-run first-innings lead before moving to 1-78 in their second innings.
But a collapse of 8-95 saw the Warriors bowled out for 173, with Joe Mennie and Chadd Sayers snaring three wickets apiece.
Marcus Stoinis didn't bat after he was granted compassionate leave following the death of his father on Tuesday.
Needing 325 for victory, the Redbacks moved to 1-54 at stumps on day three, with Jake Weatherald on 17, and Mennie on eight.
SA need 271 more runs to win, and WA skipper Mitch Marsh was confident his team would secure victory.
"It was a disappointing effort with the bat to let them back in there," Marsh said.
"But in saying that, the wicket is going up and down.
"Those are as big a cracks as I've seen at the WACA, so hopefully they'll play a part. They already have today. And they still need 270 more runs, which is a lot of runs on day four."
Bancroft scored an unbeaten 228 in WA's first-innings total of 7(dec)-514.
But he could only manage 17 in the second dig before edging Mennie behind.
However, Bancroft's recent efforts with the bat appear set to be enough to earn him selection for the first Ashes Test against England, starting on November 23 at the Gabba.
Bancroft has the potential to fill any of the three up-in-the-air positions in the Test team - opener, No.6 or wicketkeeper/batsman.
If Bancroft was chosen at No.6, it means his WA teammate Hilton Cartwright would miss out.
If he was picked to open, out-of-form Matt Renshaw would be chopped.
Renshaw has failed to reach 20 in his past nine innings in Shield and one-day matches.
In contrast, Bancroft has posted scores of 76no, 86, 228no and 17 in his past four Shield innings.
WA veteran Shaun Marsh scored 52 off 77 balls on Wednesday before being trapped lbw by Chadd Sayers.
Cartwright's Ashes hopes took a blow when he was dismissed for 18, following on from his first-innings knock of 35.
His previous Shield game yielded a pair of ducks against a star-studded NSW attack.