After an error-riddled opening by both sides, Brown booted five second-half goals in a 13.17 (95) to 5.13 (43) win in front of 33,966 fans at Etihad Stadium.

The Roos led by 11 points at three-quarter time and sealed the victory with a seven-goals-to-nil final term blitz.

"Browny is pretty close to being one of the dominant key forwards in the competition already, even at his age," coach Brad Scott said of the 25-year-old.

"Last year we were concerned about him getting double-teamed and copping the opposition's best defender every week ... it happened last year and it happened again this year but he keeps rising to the occasion."

With the roof open, conditions were perfect for football on a fine Melbourne afternoon.

But inexplicably, neither side managed to play a brand of footy anywhere near perfection in a scrappy first half.

The Roos were at least able to generate plenty of attacking thrusts but they kicked six behinds to start the match with another shot out on the full to trail by two points at the first break.

On a big occasion for both clubs and the AFL, sections of the crowd loudly voiced dissatisfaction as the players headed for the change rooms at halftime with scores 2.10 apiece.

"Kicking goals is clearly a really important part of the game but (inaccuracy) is a better problem to have than not being able to generate shots in the first place," Scott said.

"The four-quarter effort was fantastic and to be able to accelerate away at the end was pleasing."

The Kangaroos' strong finish is even more impressive when last week's physically taxing loss to Gold Coast in torrential rain in Cairns is taken into account.

St Kilda coach Alan Richardson was left with plenty of questions after the Saints turned sinners in a diabolical final term.

"Our performance was incredibly disappointing," Richardson said.

"We were absolutely smashed in the contest and beaten badly on the outside.

"What's really important is that we do something about it."

Shaun Higgins impressed through the middle for North, with 24 possessions, with Billy Hartung (24 disposals and a goal) and Jarrad Waite (24 and one) also important.

Jack Steven (26 and one) and David Armitage (27) were influential for the Saints but their three-pronged attack of Paddy McCartin, Josh Bruce and Tim Membrey failed to kick a goal between them.

On a further sour note, McCartin was reported for a clumsy late hit in the third quarter.