Unbeaten Balgownie delivered their best bowling and fielding performance of the season to overwhelm Northern Districts in Saturday's round-11 one-dayer at Judy Masters Oval.
After being dismissed for a modest 132, with Neil Ryan taking 4-28, the Magpies bowlers took charge, routing Norths for only 75.
Balgownie, who have a 12-point lead over Keira with two rounds remaining, have found some of their best form at the right time, according to all-rounder Dean Merola.
"The batting was a shade disappointing as we were looking for 175, but the bowling and fielding was the best all season," Merola said.
"The batting needs to improve but we're hitting our straps at the right time."
Opening bowler Cam Nupier took 2-5, Merola 2-7 and spinner Jamie Fleming 3-19.
Keira consolidated a top-two spot with a six-wicket win over Port Kembla at King George Oval.
Port made just 79 in 29 overs, with Jono Cook taking 4-10.
Tim Laws smashed an unbeaten 34 as Keira won with more than 31 overs to spare.
Corrimal leapfrogged University into fourth spot with a 44-run bonus-point victory over the Students at Ziems Park.
Sent into bat, Corrimal skipper Rob Fisher made the most of a life in the 30s to make 92, his highest score of the season.
Corrimal posted 9-182, with Rhys Voysey taking 4-39, before their bowlers dismissed Uni for 138.
Mitch Calder (55) top scored for Uni.
Dapto consolidated third spot with a big win over Wests Illawarra at Reed Park.
Greg Jones (84) and Richard Marsh (78) were both run out as Dapto made 6-228.
NSW Country all-rounder Dale Scifleet then took 5-15 and Kieran Doyle 4-36 to roll Wests for 73.
Wollongong put a huge dent in Helensburgh's finals hopes with a 31-run win at North Dalton Park.
Andrew Hicks (60) and Shane Fanning (35 not out) top scored for Wollongong, who recovered from 3-10 to make 9-155.
Duncan Hunt (60) played a lone hand for the Burgh (124) with Hicks taking 3-38.
Ladder: Balgownie 77; Keira 65; Dapto 49; Corrimal 48; University 44; Helensburgh 42; Northern Districts 41; Wollongong 36; Port Kembla 33; Wests Illawarra 10.