A fast start, some torrid defence and a late penalty goal were just enough for Young to snap Tumut's winning streak.
The Blues had won nine straight, starting with a win over Young earlier this season, but were dumped to second place on the Group Nine ladder after a Jesse Corcoran penalty proved to be the difference at a muddy Twickenham on Saturday.
Young crossed twice in the first 10 minutes of the clash before really being put to the test by Tumut.
When Zac Masters crashed over after the weight of possession with 11 minutes to go, the Blues looked like they would continue their roll.
However Young responded and eventually earned a penalty goal adjacent to the posts with two minutes remaining.
Corcoran held his nerve to put his team out to a 12-10 lead.
It wasn't the last twist in the clash with Jacob Toppin lining up his own penalty goal attempt after the siren.
However his attempt right in front but 39 metres out never looked likely.
Coach Nick Hall was thrilled to finally crack a two-top rival on their fifth attempt this season.
"You could say it was affected by the weather but we both had to play in it and we won," Hall said. "The result was close and it could have gone either way as it was down to a kick or a drop ball but it was what we expected.
"I thought it was good."
Young have been guilty of missing the kick against the top teams but came out firing as Nic Hall scored off a slick back line move before Jake Veney planted down a pinpoint Mitch Cornish kick to race out to a 10-0 lead.
Tumut responded when Tom Hickson scored out wide after 18 minutes before the rain returned and conditions.
Young took a 10-4 lead into half-time as both teams struggled for ball security in the horrible conditions.
Tumut had plenty of opportunities in the second half but the Cherrypickers kept turning the Blues away.
Eventually cracked when Masters stormed over but Young kept fighting and where camped on Tumut's line when Corcoran was deemed to have been stripped of the ball metres out.
He was thrilled to help his team to an important victory.
"It was very pleasing to see it go over in front of a crowd that was giving it to me," Corcoran said.
"It was good. It's a huge win too.
"We've got two byes coming up so we've only got two more regular season games so it was very big."
Young have lost four games this season, three to new ladder leaders Southcity and one to Tumut.
Heading into their first of two byes in the final month of the competition, Hall hopes it will give them plenty of confidence.
"I think it's beware Tumut on the back end of this but I think beware Young too as I think we will take confidence out of that," he said.
"It was the scalp we probably needed."
Young remain third on the ladder, four points behind Southcity and Tumut, but two points, and percentage, clear of Gundagai.