Bad light brought play to a premature end on a rain-disrupted day two at the WACA Ground with WA 5-175 in response to Victoria's 195.

Turner (49no) combined with Aaron Hardie (45) to mount a gutsy counter-attack after the hosts collapsed to be 4-53 midway through Friday's play.

The defending champions began the final session at 4-125 after a rain delay of more than 90 minutes and quickly lost Hardie, whose attempted pull shot to a Will Sutherland delivery was top-edged for a comfortable catch at mid-off.

Josh Philippe maintained the aggression, striking several gorgeous straight drive boundaries on the way to an unbeaten 25 off 29 balls.

He and Turner will look to close the deficit and build a handy first-innings lead when play resumes on Saturday as WA chases an unprecedented "six-peat" of consecutive Shield, one-day cup and Big Bash titles.

WA coach Adam Voges hailed Turner's calmness under pressure to help wrestle back the momentum for the hosts.

"It's easy to say you're going to do that but then to go out and execute it the way he did today, I thought was outstanding," he said.

"We needed someone to stand up and we've seen those two guys, particularly in pressure situations and in big games, have stood up in the past. It was great for them to have a partnership together."

Sutherland (4-44) was the clear pick of the bowlers for Victoria, hitting probing lengths and finding movement off the seam, although Scott Boland (1-27) also built plenty of pressure with a typically miserly performance.

Victoria must win outright to claim the title after WA claimed a bonus point by dismissing the visitors within the first 100 overs of their first innings.

In the event of a draw and equal bonus points, WA would prevail as the higher-ranked team on the ladder.

"There's been a lot of wickets in two days," Sutherland said.

"Hopefully it can just be a normal result and we don't have to rely on the bonus points. If that happens, we're still a good chance to win this game."

Mitch Perry's stunning catch to dismiss Hilton Cartwright for a duck highlighted an action-packed middle session in which Victoria briefly turned the game on its head.

Having absorbed 18 balls without scoring, Cartwright threw his arms at a short and wide delivery from Sutherland but it was snaffled by Perry at point with a stunning reflex catch diving to his left.

Cameron Bancroft's bright start had earlier been extinguished on 26 when he was caught at square leg off the bowling of Boland.

The Shield's leading run-scorer this season with four centuries, Bancroft has at times been vulnerable playing off his pads and fell victim to a well-laid Victorian trap.

Victoria opener Ash Chandrasinghe earlier carried his bat in one of the slowest Shield knocks in recent memory, scoring just 46 from 280 balls in more than six hours at the crease.

The 21-year-old added just five runs to his score in Thursday's middle session but his patient knock could yet prove influential given the difficult batting conditions.

Ashes hopeful Lance Morris (3-53) led WA's attack with a typically fiery performance in his first red-ball match since December.

Australian Associated Press