Will Sutherland and Scott Boland turned around the Vics' fortunes to inspire an unexpected collapse from the hosts.
After resuming at 3-290, Western Australia were bowled out for 386 to conclude an elongated morning session at the WACA.
It could have been worse for WA only for rookie Corey Rocchiccioli to swipe a couple of sixes in a wild 50 off just 29 balls batting at No.10, for an unexpected 42-run last-wicket stand with Lance Morris.
After completely dominating day one, WA contrived to lose 4-19 in the opening hour on Friday.
Sutherland was the key for the Vics, combining line and length with some raw pace to knock over nightwatchman Matthew Kelly (4), young allrounder Teague Wyllie (4) and the hard-hitting Josh Philippe (2) in quick succession.
It was Boland, however, who picked up the key scalp of Cameron Bancroft, who added just six to his overnight score before being caught by diving wicketkeeper Sam Harper down the leg side for 141.
Sutherland returned figures of 5-78 from 30.1 overs, while Boland collected 3-80 from his 31 overs.
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