Marcon, a former TAC Cup Team of the Year member who joined the Seagulls this season after spending a couple of years with VFL rivals the Northern Blues, booted three second-half goals as Williamstown outclassed Aspley 14.9 (93) to 7.6 (48).
Click here for all the latest Foxtel Cup news The Seagulls, who won the inaugural Foxtel Cup in 2011, kicked nine goals in the second half in what was a high-standard performance.
They also made a strong start to the game, dominating the inside 50s (11 to three) and kicking the first three goals.
Forward Jake Owen, coming off a five-goal haul in the Seagulls’ VFL win over Geelong last Saturday, kicked two opening-term goals to help them lead by 18 points at quarter-time.
After Williamstown big man Sean Tighe outmuscled his opponent Brendan Forbes and snapped truly early in the second quarter, the Seagulls had stretched their lead to 25 points.
But the Hornets refused to stay down and they slowly chipped away at the lead with Ryan Matthews and Matt Payne thriving on the contest.
Matthews had 13 possessions and six clearances by half-time, and also kicked a goal, as the Hornets closed the gap to seven points at the main break.
He was well supported by Payne (nine possessions and a goal) and ex-Brisbane Lions premiership player Robert Copeland (seven disposals).
Jack Johnstone (10 disposals) was prominent for the Seagulls while Marcon and Michael Gibbons both had eight possessions for the half.
The Hornets stayed in touch for most of the third term but the Seagulls kicked clear late in the stanza with four unanswered goals to extend the lead to 26 points at the final break.
A highlight of the final term was a goal to Williamstown’s Dylan Conway. It was Conway's first match back from a long layoff with a knee injury and the reaction from his teammates was priceless.
Marcon finished with 16 possessions and laid 10 tackles while Gibbbons, Tighe and Johnstone all had 18 touches.
Owen, who won the Calder Cannons best and fairest last year, finished the game with three goals from his nine touches.
Matthews was well held in the second half but still finished with a game-high 19 disposals. He also had seven clearances. Matt Payne, Austin Lucy and Copeland were also prominent early before fading late.
Adam Hughes was Aspley’s only multiple goalkicker as their forwards struggled to break free of a tight Williamstown defence.
The final round one clash is at Perth’s Paterson Stadium on Tuesday, May 27 between WAFL side East Perth and SANFL club Norwood.
WILLIAMSTOWN 4.1 5.4 9.7 14.9 (93)
ASPLEY 1.1 4.3 5.5 7.6 (48)
Williamstown: Marcon 3, Owen 3, Clouston 2, Conway 2, Gibbons, Tighe, Johnstone, Nastasi.
Aspley: Hughes 2, Nelis, Williams, Matthews, French, Payne.
Williamstown: Marcon, Tighe, Sing, Johnstone, Gibbons.
Aspley: Matthews, Payne, Hutchinson, Copeland, Forbes.