Wollongong's Shane Fanning and University's Rhys Voysey took eight wickets each to spearhead their clubs to thumping victories in the penultimate round on Saturday.
Voysey took a career best 8-27 against Northern Districts as the Students leapfrogged Corrimal into fourth spot with only Saturday's one-day round before the finals.
Uni managed only 126 but with Voysey unplayable the Students rolled Norths for just 49.
Voysey is on the comeback trail after three months sidelined with a broken finger.
"I took 5-25 once but nothing like eight wickets before," Voysey said.
"We didn't have too many runs to defend so we had a pretty attacking field set and fortunately things went our way."
After taking a wicket in his first over, Voysey went seven overs before his second dismissal.
The medium-fast bowler took his third scalp in his 10th over, two more in his 13th, another in his 14th and ended the match with wickets in successive balls in his 15th over.
Uni gloveman Andrew Page took four catches, three off Voysey, and top-scored with 39, while Neil Ryan took 5-45 for Norths.
Meanwhile, Fanning and Wollongong destroyed an inexperienced Wests Illawarra, who are heading for a winless season.
Wests were rolled for 28 off 19.1 overs, with Fanning taking 8-11 - which included two no-balls and a wide - off 10 overs.
Sundries (eight) top-scored for Wests with the game over after just 26 overs.
Balgownie clinched the minor premiership and head into the final round unbeaten after a three-wicket win over Port Kembla.
Port were dismissed for 133, led by Gavin McCauley's 41, while James Fleming (3-35) and Adam Berwick (3-19) bowled well for Bally.
Cam Nupier (43) top-scored for Bally, who reached the target with 16 overs to spare.
Keira's NSW Country all-rounder Jono Cook was the difference in the Lions' 31-run victory over Corrimal on a dreadfully slow Ziems Park outfield.
Cook (32 not out) top-scored as the Lions were restricted to 7-113, and then took 3-12 with the Cougars all out for 82 to slip from fourth to fifth.
University will book a top-four spot with a final-round win over Wests.
Dapto sealed a semi-final berth despite an away loss to Helensburgh.
Steve Blissenden (74) led the way for the Burgh (9-185), with Dapto finishing at 7-129.
Ladder: Balgownie 84, Keira 72, Dapto 58, Uni 51, Corrimal 49, Helensburgh 48, Wollongong 43, Norths 42, Port 34, Wests 12.