RAND-Walbundrie-Walla kicked three goals in the final 12 minutes to upset Brock-Burrum by four points at Walla on Saturday.
The come-from-behind victory has guaranteed the Giants a spot in the top-six while the reigning premier has slipped to third spot with one round remaining.
The home team trailed by five goals in the second quarter before working their way back into the contest through the grunt work of Jack Duck and Dean McCall and run of Daniel Lieschke, Ryan Lavery and Chris Duck.
Duck and McCall took on Azzi medal contender Matt Seiter in the ruck with the trio all having a big impact on the match.
Brock-Burrum led by almost three goals at the 16-minute-mark of the final term before Myles Aalbers, Luke Bennie and shoestring wingman Anthony Hartshorn bobbed up with late goals to pinch a memorable victory.
The ball was deep in the Saints' forward-line when the final siren sounded.
Aalbers, who finished with four telling goals, put the victory down to persistence.
"Brock-Burrum got on top of us a couple of times but the boys stuck at it and showed a lot of character," Aalbers said.
"To come back from five goals down against one of the best sides in the league was really pleasing.
"I thought our pressure and outside run was terrific.
"We're a fit side and our young legs were still covering the ground well late in the game."
Brock-Burrum defender Jeremy Luff was resolute, Seiter was tower a strength in the midfield and John-Roy Williams flashed in and out of the play.
Luke Schilg and Mitch and Josh Koschitzke were also effective.
The Saints trail second-placed Culcairn by two per cent heading into Saturday's final round.
They take on a rejuvenated Howlong while the Lions meet Lockhart.
Howlong kept its faint finals hopes alive with a 14-point win over Jindera.
The Spiders raced clear early with Daniel Sharp on fire in attack and Charlie Hamilton strong in defence before Jindera settled and finished the game full of running.
The win leaves Howlong two points outside the top-six with Beau Packer's side needing Holbrook or the Billabong Crows to slip up.
"Since losing to CDHBU, we've won our last four games and are just going out to enjoy it," Packer said.
"We're still in the mix but need things to go our way.
"All we can do is concentrate on Brock-Burrum and see what happens."
Osborne moved to top spot by defeating Lockhart by 20 points.
The Tigers set up the win in the opening term with Sam Stening, Sam Rutland, Kodie O'Malley and Will Ryan in everything.
Jesse Margosis and Jordan Harrington played well for Lockhart.
Henty avoided a potential disaster by holding off CDHBU by 24 points and Culcairn's percentage received a huge boost by crushing Murray Magpies by 244 points.