South Australia 389 and 5 for 179 (Weatherald 49, Head 49, Kelly 3-34) lead Western Australia 254 (S Marsh 63, Sayers 4-54, W Agar 3-60) by 314 runs
Four wickets to Chadd Sayers and three to Wes Agar have helped South Australia establish a 314-run lead over Western Australia with a day to play in Adelaide.
WA were bowled out for 254 partway through the third day before Jake Weatherald and Travis Head both made 49 as the home side pressed towards a final-day declaration.
WA lost 6 for 81 to concede a 135-run first-innings deficit. Sayers picked up his third wicket early in the morning session with Josh Philippe failing to a stunning diving catch at cover from William Bosisto. Cameron Green's patient 43 came to an end when he holed out at fine leg off Nick Winter. Agar nabbed his third with Josh Inglis slicing a catch to Weatherald at gully in the following over.
Joel Paris and Liam Guthrie both faced in excess of 50 balls but contributed just 30 runs between them to delay the inevitable.
South Australia scored at a healthy rate from the outset in the third innings with a declaration in mind. Henry Hunt and Weatherald combined for 85 in 22 overs but both fell in consecutive overs for 35 and 49 respectively. The platform allowed captain Travis Head to club 49 off 50 balls with six fours and two sixes before falling one short of a half-century.
Matt Kelly was the pick of the WA bowlers nabbing 3 for 34 but their batsmen will be left with a mountain to climb on the final day.