South Australia are on the verge of capitulating well short of Victoria's first innings total of 437 after finishing on 9-215 at stumps on day two of the twilight Sheffield Shield clash at Adelaide Oval on Friday.
The Redbacks trail by 222 runs - 73 shy of the follow-on target - with first-gamer Cameron Williams (14 not out) and Peter George at the crease.
It could have been worse for the hosts after a number of batsmen threw away their wickets cheaply to be 3-87 at one stage before James Smith, making his first appearance for the Redbacks in Shield cricket, fought valiantly on his way to 76.
Tom Stray (13), captain Michael Klinger (one) and Callum Ferguson (14) all tumbled in the second session of the day as Smith produced a knock years beyond his experience.
Former Test player Andrew McDonald (2-39 from 13 overs) and off-spinner Jon Holland (2-41 from 14) were the chief destroyers for the Bushrangers.
After Victoria resumed play at 7-344, the Redbacks faced fierce resistance from the Victorian tailenders before they were eventually toppled with just under half an hour to go before lunch.
A maiden Shield half-century from paceman Jayde Herrick (62 not out) who combined for a 62-run partnership with Will Sheridan (49) proved an unwelcome handful for the Redbacks bowlers.
Herrick was the biggest thorn in the hosts' side, smashing a number of his 12 boundaries late in the Bushrangers' innings.
In response, the young duo of Smith and Stray opened the batting and after a nervy start the inexperienced pair finally settled as the Redbacks reached their 50 in under an hour of play in the 13th over.
But two overs later, Stray's hesitation proved costly when he was run out at the bowler's end after Smith called him in for a second run.
The Redbacks barely had time to regather themselves when captain Klinger was bowled by McDonald after leaving a big gap between his bat and pad.
Ferguson was sent packing soon after, dismissed in identical fashion to his captain.
Rattled, the Redbacks almost lost Cooper shortly after had his cut shot not been dropped by Chris Rogers at first slip.
Cooper was again dropped by Rogers in the 29th over as the Australia A batsman began to find the boundary rope and make the most of his third life.
Smith's gracious knock, which included six boundaries and a six, eventually came to a halt three overs before tea when an arm ball from Holland struck the 23-year-old on the pad in a contentious decision, as South Australia stuttered to tea at 4-137.
Redbacks debutant Travis Head was not flustered by the pressure and looked comfortable until a rookie mistake cost him his wicket when he tried to smash a Holland delivery that was pitched too full for a pull shot and caught him plumb in front of his wicket.
Scott Boland (2-39 from nine) was in menacing form also and claimed the scalps of Cooper (42) and wicketkeeper Adam Crosthwaite (nine) late in the session.
Alex Keath (2-2 from 1.4) also picked up his first Shield wickets late when he dismissed Joe Mennie (14) and Jake Haberfield (one).
Meanwhile, Cameron White responded well to his axing as national T20 captain with 0-16 from 10 overs.