Jack Littlejohn and his Dragons are through to the grand final, the Mudgee club's first since 2016, thanks to a tremendous effort in defence.
Sunday's shut-out victory was the first time Hawks have been held scoreless since round 16, 2016 - a game that ended in an 88-0 thumping against CYMS at Wade Park.
It took 30 minutes for the first points to come and while both sides had chances early on, a blustery, cold day meant neither was able to capitalise.
Obviously everyone knows how good Hawks' attack is and to keep them to zero was pretty good with one in the bin for 10 and going against this wind in the second half.Dragons captain-coach Jack Littlejohn
Impressive early, Heta missed a pass to Jordan Baker which would have sent him over the line on the right flank to take advantage of the only crack in Mudgee's defence all day, and it was that area which pleased captain-coach Jack Littlejohn.
"Obviously everyone knows how good Hawks' attack is and to keep them to zero was pretty good with one in the bin for 10 and going against this wind in the second half," he said.
"We spoke about tightening up our middle because the young hooker [Alex Prout] is really sharp but we were real tight close to the line.
"We did a lot of work on that during the week and it worked for us today."
It looked like Nathan Potts would open the account on the end of a Jared Brodrick grubber but the three-quarter's kick went dead, Mudgee slingshotting down the other end of the field to score through Lee Hicks and open up their account.
Jack Beasley nailed the goal, and a second kick from 20 out after a penalty on the stroke of half-time following a Littlejohn break, to gift Mudgee an 8-0 lead at the break.
Hawks needed to lift after half-time and while they did they still couldn't crack the red and white wall.
They had several shots at the Mudgee's line, including one Prout attempt where his arm was dragged back despite being inches from scoring.
Chanse Burgess was given 10 in the bin not long after but, tellingly, Hawks couldn't make the visitors pay, the Dragons sealing victory thanks to an incredible effort from Harry Maynard less than a minute after Burgess rejoined them on the field.
"That's one of the best games I think we've played this year so that's great to go into a grand final off that," a chuffed Littlejohn said post-game.
"I thought we rolled through their middle a bit more, in the past we've sort of been guilty of going across field but today we put the ball under our wing and got forward."
Heta knew the prelim final would be a grind but said it just didn't go the Hawks' way, with the side falling at the same hurdle it did in 2018.
"It's gut-wrenching," he said.
"I didn't think it would be able to do it to me twice in a row, it's unfortunate but we've still got to be pleased with the year that we've had."
He gave full credit to Mudgee's defence, and their side in general, for putting the Hawks under too much pressure.
"You've got to hold onto the footy, it's been our ugly seal for us that when games get tough we go searching for points and they defended well and the scoreboard displayed that," Heta said.
The Dragons will play the Bathurst Panthers at Carrington Park on September 15 from 2pm.