Port Adelaide have all but ended North Melbourne's hopes of finishing fourth on the AFL ladder and earning a double chance in the finals, after a 76-point win at the MCG.

Port midfielder Peter Burgoyne was best afield, collecting 45 disposals as the Power won 23.10 (148) to 10.12 (72) on Saturday.

The upset means North will be hoping Adelaide, Sydney and St Kilda all lose their last match of the home and away season to retain fourth spot.

North's loss was further soured when Leigh Harding was helped off the ground in the first term after re-injuring the knee he had reconstructed in 2006.

Harding got tangled up while tacking Robbie Gray in Port's goal-square with the early diagnosis a possible posterior cruciate ligament strain.

An eight-goal-to-two third term set up the win as the Power ran all over the top of the listless Kangaroos.

The Power then piled on another five goals in the last term to smash North's confidence heading into September.

David Rodan was dangerous around the packs all day, finishing with five goals, while elusive forward Daniel Motlop, Gray and big man Toby Thurstans kicked three goals each.

With Burgoyne doing as he liked, Kane Cornes picked up 30 touches as well as nullifying the influence of North playmaker Daniel Wells.

Tom Logan and Danyle Pearce were also dominant for the Power, with Brent Harvey (27 possessions) the only North on-baller to have any real impact.

After kicking a career-high eight goals last week against Geelong, Roo David Hale again played a lone hand up forward, booting four goals.

North Melbourne looked switched on from the opening bounce, and did all the attacking.

Harding goaled from a free kick for tackling Port ruckman Dean Brogan, and that was quickly followed by a goal from Corey Jones.

And when Daniel Pratt's thumped one through from 65 metres, the Roos had an early 19-point lead.

But Port worked their way back into the contest with goals to Burgoyne and two to Gray to trail at quarter-time by just five points.

North started the second like they did in the first but Port fought back well.

Goals to Rodan and Pearce saw Port draw level before two from Cassisi saw Port grab an 18-point buffer at halftime.