Culcairn's season is still alive after a thrilling one-wicket win over The Rock Yerong Creek.
Last pair Jack Retallick and Dai Jenkins needed eight runs for the win.
"There was a dropped catch off Jack, he skied one," team-mate Vince Chaffey said.
The home outfit posted 165 with long-time star Todd Hannam top-scoring on 44, while Mitch Way nabbed 3-13.
Opener Chaffey contributed 35, but No.8 Retallick's 24 not out was vital.
"We said before the game if we want to play finals we have to win," Chaffey said.
Mark Alcorn (4-16) was terrific.
IN OTHER NEWS:
Elsewhere, Holbrook's Corey McCarthy starred (3-21 and 67no) in the win over Walbundrie, despite Hayden Wardius hitting 95.
Brock-Burrum's Keith Tallent took 4-17 to skittle Walla for 70, Osborne's Darren Howard struck 88 in the win over Rand, while Lockhart's Jordan Harrington posted 68 in victory against Henty.