Victoria 0 for 72 trail South Australia 244 (Cooper 118, Lehmann 56, Boland 7-54) by 172 runs
Boland followed his 6 for 49 in last week's rout of New South Wales by taking a 7 for 54 to bowl the Redbacks out for 244 after they had won the toss and elected to bat on an MCG surface that again featured plenty of grass.
Cooper and Jake Lehmann were again lone hands for the Redbacks. Following on from their respective centuries against Queensland at Adelaide Oval they again found themselves together at 3 for 45 in the 11th over after Boland claimed his first scalp in Conor McInerney. Earlier, Peter Siddle accounted for Jake Weatherald while Callum Ferguson was adjudged lbw to Chris Tremain despite the ball appearing to deflect off a healthy inside edge.
Cooper and Lehmann added 98, with the latter reaching fifty for the third time in four innings this season. But just as they were taking control he dragged a wide half-volley from Boland back onto his stumps.
Cooper pushed onto his second straight century and the 12th of his first-class career. He and Harry Nielsen shared an 88-run stand to move the total to 4 for 231 before Boland swung the game in one spell.
He found the outside edges of both Nielsen and Cameron Valente in three balls. Two overs later Cooper nicked a wide one to give Boland his fifth five-wicket haul in first-class cricket and Victoria wicketkeeper Seb Gotch his fifth catch of the innings.
The Redbacks tail folded losing their last six wickets for just 13 runs. Boland took five wickets in four overs before Fawad Ahmed claimed the last. Boland now has 22 Shield wickets in just five innings so far this season.
Victoria's openers then raced to stumps reaching 72 without loss. Travis Dean did the bulk of the damage striking eight boundaries in 56 not out from just 79 balls. Marcus Harris was more circumspect and will begin day two on 16.