Victoria 7 for 186 (Morris 3-40) trail Western Australia 9 for 391 dec (Inglis 115, Bancroft 113, Paris 102*)
Paris and Josh Inglis took their seventh-wicket stand to 142, the latter making his third century of the season, before the Western Australia pace attack combined to reduce Victoria to 7 for 143 although they made it to stumps without further loss.
After bringing up his century from 143 balls, having previously had a best of 93, Paris made the first breakthrough when Marcus Harris edged to slip.
However, it was either side of tea that the game really swung when Morris made his mark. He struck twice in an over before the break, trapping Travis Dean lbw and having Peter Handscomb hooking to long leg, then added Nic Maddinson shortly after the resumption playing a loose drive.
Cameron Gannon joined in when Matt Short played a poor shot off the back foot to edge to Inglis which left Victoria 5 for 85. Their innings was steadied for a while as Seb Gotch and James Pattinson added 53, but both fell to Matt Kelly - Pattinson well held, low down, at first slip and Gotch driving to point.
It appeared Victoria could be bowled out before the end of the day but Will Sutherland and Scott Boland showed better application.
Western Australia had resumed on 6 for 291 and in the sixth over the day Inglis reached his century from 132 balls. When he departed, Paris was accompanied by Kelly and Gannon as he brought up his hundred before the fall of the ninth wicket prompted Shaun Marsh to declare knowing their hopes of making the Shield final rest on victory and time was of the essence.
The scorecard had a curious look with three centuries in a total under 400 then and the next-highest score being 13.