North Melbourne has gone down to a disciplined Fremantle by 78 points at Optus Stadium.

Justin Longmuir's team established a healthy early lead, and the closest the Roos got from then on was 19 points early in the second quarter.

Pressure forward Sam Switkowski ran down Todd Goldstein and kicked truly to set the tone for Fremantle in the first three minutes.

Debutant Jye Amiss and Sean Darcy followed with contested marks and conversions, and Bailey Banfield iced the term with a snap and a set shot.

After a slow start, the Roos began to impose themselves through West Australian forward Cam Zurhaar, as he jumped over a pack with a Mark of the Year contender and jagged his team's first.

Ruck recruit Callum Coleman-Jones then reeled the margin back to three goals with a snap over his shoulder, having won a free kick for holding the man in the pocket.

A moment of magic from Nathan O'Driscoll, as he retrieved a ball that was all but a behind, set up a goal for Brennan Cox to replenish Fremantle's lead.

After North successfully fought to contain the hosts for much of the second term, Michael Walters snapped two in time on, and pushed the margin out to 38.

The third quarter was a grapple to start, but the Dockers' pressure mounted.

DOCKERS v KANGAROOS Full match coverage and stats

O'Driscoll slotted a set shot from the pocket after a tackle steered a clearance from Jason Horne-Francis over the line.

The Kangaroos enjoyed sequences with possession thereafter, but Fremantle lived up to the stingy reputation they've forged so far this season and didn't concede a major.

Three goals in time on to Switkowski, Jordan Clark and Amiss helped the hosts out to a 64-point lead at the last change.

Zurhaar added his second and the Roos' third late in the final term, but not before Hayden Young and David Mundy put their names on the scoresheet.

Lachie Schulz applied the finishing touch after the siren to send Fremantle into triple figures.

Fingers crossed for Ben McKay

Having been substituted out twice and been suspended for one match so far this season, the defender will have hoped for continuity with his body in order to build on his impressive key position craft.

Instead, the 24-year-old left the field limping in the third term, and was examined by club doctors on the Roos' interchange bench.

North Melbourne's personnel crisis in the key positions is set to ease with Nick Larkey to return from his own suspension, which frees up Josh Walker to return to the backline.

For McKay however, it would be a bitter blow if he is to miss a stretch. Everyone at Arden Street will hope for better news for the No.23.

FREMANTLE                        5.1   8.5  12.9  15.12   (102)
NORTH MELBOURNE         0.2   2.3    2.5    3.6      (24)

GOALS  
Fremantle: Amiss, Banfield, Switkowski, Walters 2, Clark, Cox, Darcy, Mundy, O'Driscoll, Schultz, Young
North Melbourne: Zurhaar 2, Coleman-Jones

BEST 
Fremantle: Brodie, Brayshaw, Clark, Darcy, Banfield, Treacy
North Melbourne: McDonald, Thomas, Young, McKay, Zurhaar

INJURIES 
Fremantle: Switkowski (head)
North Melbourne: McKay (knee)

SUBSTITUTES 
Fremantle: Neil Erasmus (replaced Sam Switkowski in fourth quarter)
North Melbourne: Jack Mahony (replaced Ben McKay at three-quarter time)

Crowd: 37,040 at Optus Stadium