Wests Cardinals broke a 7-7 deadlock with two runs in the eighth inning to stun Berkeley Eagles 9-8 in Saturday's round four clash at Cringila Park.
Eagles scored three runs in the first inning and led 7-5 following a four-run fifth inning, but couldn't hold on against the reigning premiers.
Eagles out-hit Cardinals 11-8 but had Chad Blanch ejected midway through the match, while four Berkeley errors also proved decisive.
Jack Green went 3/4 for Cards, while Aaron Tritton and Josh Matavesi were 2/5 for Eagles, with Matavesi also contributing an important RBI.
Cardinals starting pitcher Scott Sartori threw seven innings for nine hits, seven runs and struck out 11 batters.
Josh Doyle gave up seven hits in his five innings of pitching for Eagles, but was let down by his fielders, with three Cardinals runs coming off errors.
Meanwhile, Northern Pirates starting pitcher Ben Gibson and closer Lachlan Crawley also did the damage with the bat in Pirates' 6-1 win over Kiama Braves at Dalton Park.
Gibson dominated on the mound, throwing seven innings for six hits with eight strikeouts and conceded just one run.
Gibson was also 2/3 with the bat, while Crawley finished off the job in pitching relief, plus went 2/4 with an RBI.
Brendan Capri and Kelly Bullimore were 2/5 for Braves, who were out-hit 10-8 and made three errors to Pirates' only one.
Dapto Chiefs scored seven runs in the first inning in an 11-0 thrashing of Shoalhaven Mariners at Hector Harvey Reserve.
Tyson Graham scored a grand slam homer in the first inning, before being walked in his other at-bats.
In Saturday's round five, Mariners and Eagles are looking for their first win of the season at IBL Field, Cardinals host Pirates and Chiefs are at home to Braves.