In a cracking game of footy that had four lead changes and hung in the balance with seasons on the line, Macquarie eventually edged out Cessnock to qualify for next weekend's grand final.
Dean Morris crossed for a hat-trick, featuring back-to-back tries in the closing quarter, but Malik Deyaolu broke the deadlock with a miraculous effort in the 79th minute.
Macquarie rallied late with 14 unanswered points to beat Cessnock 26-20 in Saturday's preliminary final at Lyall Peacock Field. Conditions were wet, cold and windy.
The Scorpions now get a shot at the 2022 title, meeting minor premiers Maitland in the decider at McDonald Jones Stadium on Sunday, September 11.
The Goannas, having led by eight points on the hour mark and surviving two elimination semis over the last fortnight, are now knocked out.
Macquarie winger Morris managed to find the line on three occasions, but Deyaolu's try was the clincher as the second-rower somehow grounded the ball just inside the field of play.
Deyaolu was chasing a grubber from five-eighth Jeremy Gibson, who stepped up in the absence of injured playmaker Bayden Searle (broken leg).
Bobby Treacy was also sidelined for the Scorpions, having been found guilty of a crusher tackle at the judiciary during the week and suspended for three games.
Kerrod Holland, who hit the top of the upright with a sideline conversion attempt at 20-all, overcame an ankle injury to play a strong hand for the home side.
In a moment of mayhem right on full-time, Macquarie's Jordy Mitchell kicked the ball away in celebration but it precariously stayed in the field of play for looming Cessnock chasers before going over the sideline.
Cessnock's Honeti Tuha nabbed a double, including one in each half, both excellent individual efforts.
Harvey Neville and Harry O'Brien also recorded four pointers for the visitors.
The Goannas were in front 10-4 and 20-12.
It was 10-all at half-time, one of three times scores were level during the 80 minutes.
Macquarie's Matt Moon went off injured midway through the second half.
MACQUARIE 26 (Dean Morris 3, Luke Higgins, Malik Deyaolu tries; Kerrod Holland 3 goals) defeated CESSNOCK 20 (Honeti Tuha 2, Harvey Neville, Harry O'Brien tries; Sam Clune 2 goals).
