St Kilda champion Nick Riewoldt has nominated the Western Bulldogs and Port Adelaide as the teams most likely to threaten the top four come September.

The Bulldogs have gone 6-3 since their round 12 bye, and are fresh off a remarkable performance in which they held Essendon goalless for three-and-a-half quarters, piling on 21 consecutive goals after conceding the first of the game.

Meanwhile, the Power have roared back into form in the last fortnight, posting big wins over the Swans and Bombers after three straight losses.

Both sides are currently 10-10, with just under seven per cent separating the eighth-placed Power from the 10th-placed Bulldogs. The Crows are sandwiched between the two teams in ninth.

Riewoldt believes the teams' unconventional game styles set them apart.

“It’s unique compared to the way the rest of the competition wants to play," Riewoldt told SEN Breakfast.

"They’re both playing a really unique style.

“If you’re a bit off defensively, they make you look silly. Both of these teams.

“Port Adelaide through the corridor, they’ve got great young players. The Bulldogs we know they like to flick it around.

"It’s just really unique."

Port Adelaide faces North Melbourne away followed by Fremantle at home to close the home and away season, while the Bulldogs play the Giants in Sydney before hosting Adelaide in Ballarat.