The Vikings will play in their eighth consecutive grand final, while the Whites will be forced into a fight to save their season following the 30-22 nail-biter at Viking Park.

Vikings five-eighth Isaac Thompson finished with a 20-point haul and scored a try in the final minute to destroy the Whites' hopes of avenging their exit from last year's finals.

The Vikings have played in every grand final since 2009 in a decade of dominance that has delivered five premierships.

But ACT Brumbies and Tuggeranong half Joe Powell said the pain of losing to Royals after the siren last year was driving the team to greater heights.

Powell was left out of the Wallabies squad on Friday for the Rugby Championships after being a shock selection in the mid-year training camp.

Instead of chasing Wallabies gold, Powell wants to taste sweet John I Dent Cup success after earning a start in his fourth grand final.

"That passion is still there, especially after last year," he said. "Losing to Royals definitely stung a few of the boys, so I'd say there's more passion than ever now to win this one.

"We don't want the same feeling as last year, that was pretty awful. It was a tight one to get through against Queanbeyan so I'm glad we survived that."

Powell and a host of Brumbies are back in Canberra's club rugby competition after they were bundled out of the Super Rugby finals last week.

But while Powell, Jarrad Butler, Robbie Coleman, Les Leuluaialii-Makin and Andrew Smith all played in the major semi-final, it was Thompson who took control with a dominant display.

Thompson's boot kept the Vikings in front, slotting three conversions, two penalties and a drop goal to always have a slight edge against the fired-up Whites.

But every time the Vikings looked to be breaking clear, the Whites found a way back into the contest despite frustrating decisions and stunted possession.

They trailed 10-0 just before half-time and then fell behind 23-15 with 10 minutes left, before No.8 OJ Noa forced his way over in the corner to cut the margin to just one point.

The Whites tried to snatch the lead but their attacking possession was continually thwarted and Thompson took control of the closing minutes and regathered a grubber in the last minute to score and ice the game.

"Isaac was excellent, that was a big focus for us. Isaac needed to direct us around a little bit better and he did that," said Vikings coach Tim Sampson.

"Tight games have been the trend all year against Queanbeyan and if we play them again I think it will be another tight one. It's always a relief to go straight through."

The Whites will play the winner of the minor semi-final next weekend, with defending premiers Royals and the Gungahlin Eagles going head to head on Sunday in an elimination match.

The Whites were ousted from premiership contention last year when they lost both of their finals and failed to secure a grand final berth.

But coach Adam Fahey is confident his group has moved on and is ready to refocus for a preliminary final next weekend.

"It was very frustrating, we've regrouped every week this year," Fahey said. "We've changed a few things this year, it's a different attitude and a different group. The past doesn't haunt us, we know what to do.

"We got no back-to-back possession, they're a quality side and they know how to put you away."

AT A GLANCE

John I Dent Cup: TUGGERANONG VIKINGS 30 (J Rakic, E Suavai, I Thompson tries; I Thompson 3 conversions, 2 penalties, drop goal) bt QUEANBEYAN WHITES 22 (S Tai, B Spears, OJ Noa tries; B Spears 2 conversions, penalty).

JOHN I DENT CUP MINOR SEMI-FINAL

Sunday: Gungahlin Eagles v Royals at Viking Park, 3.20pm.

Major semi-final results

Second grade: Queanbeyan Whites 23 bt Tuggeranong Vikings 16.

Colts: Royals 31 bt Tuggeranong Vikings 5

Women's major semi-final: Tuggeranong ViQueens 20 bt Uni-Norths Owls 17

Women's minor semi-final: Royals 55 bt Gungahlin Eagles 5

First division

First grade: Gungahlin Eagles 68 bt Hall 12

Second grade: Tuggeranong Vikings 17 bt Wests 0