And what a thriller it was.

Twelve months after putting in a horror performance when taking on arch rivals Gundagai for top spot on the Group Nine ladder, this time around Tumut kept on fighting to take a 20-18 victory on Saturday.

In a fast, tough and physical clash where tempers threatened to boil over at any moment it was Gundagai who jumped out to a 12-0 lead when captain Luke Berkrey forced his way over after 29 minutes.

However the Blues responded scoring three straight tries to hit the front for the first time with 26 minutes left to play.

Gundagai hit back when Jake Elphick charged over with five remaining and it looked like the two teams could have played out their second draw of the season.

However James Luff hit the post with his conversion attempt to see the Blues hold onto a two-point buffer.

Gundagai had a late chance when Mathew Lyons made a big break up the middle but the Blues scrambled to diffuse the situation to take just their second win over their arch rivals in the past 10 years.

Co-coach Dean Bristow, who returned from a back injury at five-eighth, was thrilled with the spirit the side showed to earn themselves home ground advantage in next week's final and become the first team to beat Gundagai all season in the process.

"It has been a long time since we've won down here so it feels great," Bristow said.

"It is probably the highest quality match we've played in all year, it was fast and everything you would want in the derby.

"To come away with it and get home ground advantage for next week, especially with a fair few wounded troops is massive for us."

Bristow is hoping to have some more players at his disposal with a place in the grand final up for grabs.

While he came back into the side for the first time since round three, and was joined by Connor Massen and Parish Bellette in the back line, Adam Pearce and Jacob Toppin both sat out the clash after picking up injuries in the win over Brothers last week while Jacob Sturt injured his ankle at training on Friday night.

Bristow is hoping they will all be fit for the semi-final.

"Hopefully we can all regroup and have a selection headache next week to try and pick a team to face Gundagai again," he said.

Luff opened the scoring after 17 minutes as he forced his way over from dummy half before Berkrey capitalised on a penalty to double their lead.

However after missing a few opportunities close to the line Lachlan Bristow got the Blues on the board four minutes out from half-time after being gifted possession when Damian Willis was penalised with the ball 20 metres out from his own line.

A Luff penalty goal gave Gundagai a 14-6 lead at the break.

Twice both teams were down to 12 men with Zac Masters and Tyron Gorman first given their marching orders after a scuffle before Tevita Aroha-Tuinauvai and Berkrey were sin binned just before half-time.

Tumut fired out of the blocks in the second stanza as Michael Fenn forced his way over after three minutes before Jordan Anderson put them in front with his try with 26 minutes to play.

Brayden Draber kicked what ended up being a decisive penalty goal six minutes later before Elphick crashed over to set up a frenetic finish.

Bristow thought the way his side responded in the second half was key.

"It was probably a reflection of our training to be honest," he said.

"We took a while to find our groove but just got back to doing what we do - getting our big boys to go forward.

"We had a couple of opportunities down there and we took them.

"That is what the footy is all about.

"The big thing we spoke about at half-time was coming out and scoring first.

"It was massive for us to come out, set the scene and we showed some grit to hang on towards the end after a strong Gundagai challenge."