Melbourne ruckman Max Gawn has produced the greatest quarter of his career to lead the Demons to an 83-point preliminary final demolition of Geelong in front of 58,599 fans at Optus Stadium.

In just six minutes of actual playing time during the third quarter of Friday night’s match, Gawn kicked four magical goals to help turn a 29-point halftime lead into a monster 70-point margin.

The Demons slammed through eight goals to nil during the third-quarter romp on the way to the 19.11 (125) to 6.6 (42) triumph, meaning they are now just one win away from snaring their first flag since 1964.

Melbourne will meet either Port Adelaide or the Western Bulldogs in the September 25 grand final in Perth.

But the win over Geelong might come at a cost, with star defender Steven May suffering an injury scare to his right hamstring in the opening term.

Although May was able to play on until being subbed out in the third quarter once the result was settled, he looked restricted at times and is set to undergo scans to determine the extent of the injury.

Gawn finished with a career-best five goals from 19 disposals in a best-afield display, while Christian Petracca (32 disposals, eight clearances) and Jack Viney (34 disposals, nine clearances) were also influential.

Cats star Patrick Dangerfield (29 disposals, 10 clearances) tried his heart out, but Geelong were outgunned from the outset.

The result could mark the beginning of a belated freefall for the Cats, who have missed the finals just twice since 2004, and have reached the preliminary final stage in five of the past six years.

The Cats fielded 11 players who were 30 years or over on Friday night, and they face a fight to keep their premiership window open in 2022 and beyond.

The nature they were dismantled by Melbourne is cause for concern, with the Cats made to look old and slow throughout the match.

Melbourne led by 27 points at quarter time, with Geelong’s structure crumbling under the Demons’ quick-fire run and spread.

Alarm bells were ringing for Geelong when the scoreline read 60-19 late in the second term.

Goals to Tom Hawkins and Isaac Smith to finish the half closed the margin to 29 points, but the third quarter became the Gawn show as the All-Australian ruckman produced a series of stunning highlights.

Gawn’s first goal of the quarter was something to behold, with the ruckman doing his best impression of a midfielder by receiving a handball from Petracca after a centre bounce before nailing a 52m goal on the run.

His third goal of the quarter was a show of strength, with Gawn outmuscling Mark Blicavs in the ruck before snapping truly from a tight angle.

And he set the crowd alight a short time later when he took a strong contested mark to boot his fourth for the term – and fifth for the match.

The Demons kicked 8.2 to 0.1 for the quarter, with Geelong players left stunned by the shellacking.

Chants of “Gawny, Gawny” erupted around the stadium as Gawn lined up for goal No.6 in the final term, but the 50m set shot sailed out on the full.

“I haven’t done that before,” Gawn told the Seven Network when asked about his goalkicking heroics.

“I’m not normally a goalkicker. That stoppage goal – I probably won’t be able to do it again in my life.

“We want to be able to win the grand final. That’s what the target is.

“This is really nice, but we haven’t broken the drought until we’ve done something in two weeks.”

-AAP