North Melbourne has gone down by 21-points to Port Adelaide in a high-scoring affair at Alberton Oval.

The Roos got off to a flying start, kicking seven goals in the first term, with Paul Ahern kicking an equal game-high 3 goals.

But after taking a lead into the first change, the Kangaroos trailed for the rest of the game, with the Power too good on the day.

Losing both pre-season games won't be a concern for the Kangaroos – without ruckman Todd Goldstein (rested) and midfielder Ben Cunnington (thigh) against the Power – but a calf injury to defender Marley Williams will be a worry ahead of their round one clash with Fremantle at Optus Stadium on March 24.

Jared Polec was a standout in his first game against his former club, Ahern looked lively,and Bailey Scott showed plenty of promise.

After an underwhelming first season with the Power, Tom Rockliff turned it on against the Roos, dominating with a game-high 42 disposals, 17 marks and nine clearances.

Rockliff struggled with a shoulder injury last year, but is reaping the benefits of a great pre-season and showing why the Power signed him to a lucrative four-year deal at the end of 2017.

The Power claimed their first victory of the pre-season – 19.9 (123) to 16.6 (102) – in a free-flowing hitout heavy on scoring and low on congestion.

Youngster Zak Butters punched his round one ticket with another strong showing, kicking three goals, while Xavier Duursma, Connor Rozee and Willem Drew could make it four debutants for the Power in their season-opener with Melbourne on March 23.

Whether defender Jarrod Lienert is there remains to be seen after he left the game in the second quarter with knee soreness.

Ruckman Paddy Ryder came off worse for wear in a fourth-quarter collision with teammate Robbie Gray and didn't finish the game with concussion.

Fourteen goals were kicked in the first quarter – and 22 in the opening half – as the set starting positions opened up plenty of scoring opportunities. 

PORT ADELAIDE                     7.1       12.4     15.8     19.9 (123)

NORTH MELBOURNE             7.2       10.4     12.5     16.6 (102) 

GOALS

Port Adelaide: Butters 3, R Gray 2, Rockliff 2, Byrne-Jones 2, Lycett 2, Westhoff 2, Powell-Pepper, Boak, Marshall, Motlop, Amon, Watts

North Melbourne: Ahern 3, Turner 2, Scott 2, Higgins 2, Ziebell 2, Wood, Hall, Brown, Polec, Campbell

BEST 

Port Adelaide: Rockliff, Boak, Watts, Duursma, Bonner, Lycett

North Melbourne: Ahern, Polec, Higgins, Hall, Scott, Thompson 

INJURIES

Port Adelaide: Lienert (knee), Ryder (concussion)