Unheralded Culcairn all-rounder Jack Retallick survived a dropped catch to steer his side to a thrilling last-wicket win over TRYC at Yerong Creek.
Retallick finished with 24 not-out as he and number 11 put on the last eight runs for victory.
Culcairn, chasing 165, finished with 9/165.
Earlier, Todd Hannam with 44 top-scored for TRYC, while Mitchell Way (3/13) and two wickets each to Riley and Lachie Knobel ensured the Lions were in the game.
Culcairn was given a steady start by Vince Chaffey, 35, but when the side slumped to 7/117 and 8/131, it looked no chance before Retallick's heroics.
Osborne outplayed defending premiers Rand at Osborne to win a vital clash by 24 runs, with Osborne veteran Darren Howard top-scoring with 88.
The home side batted first and posted a very handy 7/181, with Howard's innings the feature. Dan Lieschke 1/16 and Clint Ralston 1/27 were the best of the Rand attack.
Despite an excellent 60 from mark Kreutzberger and 38 from Will Swift, the Pigeons could not get on top of the accurate and disciplined Osborne bowlers.
The loss saw Rand drop out of the top six, while Osborne are equal in fourth with Lockhart.
Flag favourites Brock Burrum confirmed its status with a thumping win over top team Walla, winning by nine wickets at Walla.
Nothing went right for the home side after they won the toss and batted. Mark Taylor, with 23, was the best as they were bowled out for 70.
All the Saints' bowlers dominated with Keith Tallent taking 4/17, while Darcy I'Anson 1/18 and Jordan Schilg 1/10 both bowled superb eight over spells.
Brock Burrum made quick work of the run chase, with Tallent making 30 and wicketkeeper Davey Williams 26 as it won with 26 overs to spare.
Holbrook has moved into second position on the ladder after defeating Walbundrie by nine wickets at Walbundrie.
Batting first, the Tigers' innings was saved by a superb 95 from Hayden Wardius off just 76 balls. He came to the crease with Walbundrie reeling at 5/31.
Corey McCarthy and Lewis Bowen shared the first five wickets, while Eddie Edlinger and Nick Locke bowled well in the middle part of the innings.
In reply, Holbrook made a steady start against superb bowling form Brett Mugridge 0/8 off eight overs, before Corey McCarthy, 61 no, and Hamish Mackinlay, 55 no, added an over-100 stand.
Lockhart and Henty played out a thriller at Lockhart, with the home side getting home by three wickets and 11 balls to spare.
Henty looked in good shape after winning the toss and making 5/176, with Shannon Terlich and Daniel Hore-Smith both making 39 and Daniel Terlich 35.
Lockhart's two best bowlers also became their two best batters, with Jordan Harrington 68 and Jackson Weidermann 54 putting on a century stand.
Daniel Terlich 3/28 and Shannon 2/37 instigated a middle order collapse. The win by Lockhart had it jump ahead of Henty on the ladder.
THIS WEEK - ROUND TEN
Henty v Walla
Holbrook v Walla
TRYC v Rand
Culcairn v Lockhart
Walbundrie v Osborne