Ben Roddy scored four tries, including the winner with three minutes to play, to snap a Tumut's 19-game losing streak against Gundagai and win through to the grand final.
Nine years ago Roddy scored in the Blues' last win over the Tigers and he delivered an inspired performance to reverse almost a decade's worth of outs.
The centre scored both of Tumut's first half tries before scoring the last two of the game as the Blues overcame a 14-point deficit midway through the second half to set up a showdown with Southcity on Sunday.
Roddy was only one of three players in the Tumut line up who have ever beaten Gundagai before the thrilling 28-26 victory at Harris Park on Sunday.
However he didn't want to take too much credit.
"It was a good team effort," Roddy said. "We had to come up with something to get over Gundagai, they are a quality outfit, and we really needed to dig deep but with the wind in the second half we were pretty confident and we never let it go."
Co-coach Dean Bristow couldn't think of a better way to end their horror streak against Gundagai.
He was thrilled with Roddy's performance and that of the entire team as they kept fighting to keep their season alive.
"They way the side this been this year we've dug deep for each other," Bristow said.
"We knew it wasn't us down there a couple of weeks ago and we were hoping they might underestimate us a little bit.
"We always believed in ourselves, have proved in the last couple of weeks that we are a good side and it showed late in the game."
It was a close first half between the two arch rivals but Gundagai centre Mathew Lyons proved to be too much of a handful to help his side to a 20-12 lead the break.
The sides were going try-for-try before Lyons scored his second with 11 minutes left in the half.
With a good breeze at their backs in the second half the Blues needed to be the first to score, but instead it was the premiers who continued their charge as Dylan Murdoch went over 11 minutes into the second half.
However the Blues kept coming and off the back of a couple of penalties Tom Warner scored to reduce the margin with 23 minutes remaining.
Tumut then had three straight sets on the Gundagai line but couldn't find a way through but even that didn't dint their confidence and with 11 to go Roddy completed his hat-trick to make it a two-point game.
Bristow then made an error at the back with seven left but the Blues defence held firm, forcing Field into error.
The Blues were then helped down the field by another penalty before Roddy scored from a Jacob Toppin kick as the ball ricocheted off Lyons then Roddy's knees before he regathered to make it four tries.
Gundagai weren't done with yet as they pounced on a short kick off only for another error giving the Blues the ball back metres from their try line as they held on for a dramatic victory.
Bristow thought the side's attitude was key.
"We knew we would be able to get a bit of momentum in the second half (with the wind) and it was just about hanging tough but the character of our side to come back, especially after they come out scored and definitely had the momentum, to wrestle back the momentum and find that killer punch I deadset couldn't be more proud of them," he said.