Minor premiers Keira and second-placed Helensburgh will take a huge advantage into this Saturday's Illawarra cricket semi-finals, while Corrimal clinched fourth spot with a win over Northern Districts.
Keira finished the 18-round one-day season undefeated after beating Wollongong, while defending champions Helensburgh locked in second spot with an 89-run thrashing of wooden-spooners University.
Josh Piper made a fine 79 for the Burgh who posted 174, then rolled the Students for 85, with Luke McGregor making 38.
Keira take on Corrimal in one-semi-final at North Dalton Park, while the Burgh face Wollongong (third) at Figtree Oval.
The top two clubs need only a "losing draw" to advance to the final, meaning if they bat second and are not bowled out they will qualify for the final.
Expect tactics to play a key role with the lower-placed clubs Wollongong and Corrimal knowing if they win the toss they must bat second to negate their higher-placed opponent being able to make the final with a "losing draw".
The rules for the finals were panned by three club captains involved in the semis.
Helensburgh skipper Tim Lloyd doesn't like the losing draw rule even if it will advantage his side on Saturday.
"If you're in trouble as the higher-placed team you can try and dig in and get a losing draw," Lloyd said.
Keira (5-157) beat Wollongong (156) in the final round and Lions skipper Graeme Batty said the losing draw should have been scrapped for the finals.
"You want the best teams to make the final. This system doesn't do that," Batty said.
Corrimal skipper Rob Fisher described the rule as "a joke".
"It's terrible. We could have Keira eight or nine down and they can't win the game but they'll get through to the final. Maybe it's not too late to change it," Fisher said.
A fine 86 from Fisher and unbeaten 73 from Joe McDevitt ensured Corrimal (208) beat Northern Districts (141) to seal fourth spot.
In their return season to first grade Corrimal have their top three grades in the semis and finished second in the club championship.
Meanwhile, Dapto finished fifth after thrashing Wests at Reed Park. Dapto declared at 3-231, and rolled Wests for 120 with Maciu Gauna making 76.
Finally, Balgownie (5-152) beat Port Kembla (151).