NORTH Melbourne remains undefeated after escaping with a contentious seven-point triumph over St Kilda in Drew Petrie's 300th game at Etihad Stadium on Sunday.

The Kangaroos put the cue in the rack leading by 26 points at the 10-minute mark of the final term, and almost watched their perfect 7-0 start to the season slip away as the gutsy Saints refused to throw in the towel in a frantic finish.

WATCH: The final two minutes

Inspired by skipper Nick Riewoldt, the Saints booted four unanswered goals and incredibly leveled the scores with an eternity left on the clock as Alan Richardson's men finished all over the League leaders.

A controversial free kick and long-range point to Todd Goldstein gave the Roos the lead with just 90 seconds remaining, however the Saints had their chances to steal a famous win before Mason Wood iced the match.

Full match coverage and stats

Wood won a holding the ball decision in the forward pocket with 22 seconds to go and kept the ball while the 30-second shot clock ticked down towards zero.

The final siren sounded first, though, in the first such incident since the shot clock was made visible on the scoreboard this season.

Players will keep manipulating the shot clock: Wood

"I thought it was very well done, given that they're the rules. If that had of been one of our players I would've thought 'gee, great composure young man'," Saints coach Alan Richardson said post-match.

"It was very frustrating though, it was the longest 30 seconds in the coach's box I reckon I've ever had.

"Is it a good look? I'm not sure. But given the rules and the circumstances, I thought he did a really good job."

Wood rubbed salt into the wounds of Saints fans by threading a brilliant set shot to get the Roos over the line 11.16 (82) to 11.9 (75).

It was an unforgettable finish to an otherwise dour game, which only came to life after Riewoldt's fire-starting third goal at the 10-minute mark of the last term.

Jack Billings, Tim Membrey and Josh Bruce all had ice flowing through their veins as they then kicked truly and the smallish pro-Saints Mother's Day crowd threatened to lift the roof off Etihad Stadium.

However, the Kangas' experience told in the frenetic final passages.

Five talking points: St Kilda v North Melbourne

"We did what we had to do today. We played some pretty good footy at times," Roos coach Brad Scott said post-match.

"St Kilda defended really well, they made it really hard for us to play the way we wanted to with ball in hand."

It's the first time since 1979 that North has gone through undefeated after seven games and with Essendon then Carlton to come, Brad Scott's men have a golden opportunity to tighten its stranglehold on a top-two spot.

Earlier, North's workmanlike effort had found all the answers to withstand the Saints' challenges.

Fittingly, Petrie played a key role, booting two important goals and being the Roos' most threatening target with the in-form Jarrad Waite (one) shackled by Sean Dempster.

SHOWREEL: Petrie stands and delivers in 300th

The Roos' forwards were well serviced by a workhorse midfield, led by Ben Cunnington, Jack Ziebell and Andrew Swallow, with North controlling clearances (41-29), contested ball (145-135) and inside 50s (61-50).

Defender Robbie Tarrant continued his good form by blanketing Bruce, but Riewoldt (24 touches) turned in another vintage performance on a wing and up forward as he edges towards confirming he will play on next season.

Fellow veteran Leigh Montagna, Jack Newnes, Sam Gilbert and Shane Savage were also standout performers, but they couldn't stop the Saints slipping to a 2-5 start to the year and they have now only won one of their past eight matches at its Etihad Stadium home.

MEDICAL ROOM
St Kilda: Nick Riewoldt was sore in the dying stages, while David Armitage copped a head knock and both will be monitored this week. The Saints also lost Jack Sinclair to a corked calf before the bounce.

North Melbourne: Shaun Higgins hurt his right knee when Sean Dempster fell across his leg as he snapped an important third-quarter goal, but was fortunately escaped serious injury and returned to the action. Daniel Wells came off with a suspected hamstring issue, but amazingly returned to play in the final minutes. Sam Wright was a late withdrawal due to an ankle he injured in last week's win over the Western Bulldogs. 

NEXT UP
The undefeated Roos have a golden opportunity to go 8-0 for the first time since 1978 against Essendon back at Etihad Stadium next Saturday, while the Saints face a tough trip to take on West Coast on the rebound from another poor road defeat on Sunday.

Drew Petrie chaired off after his 300th game. Picture: AFL Media

ST KILDA                          2.3    3.7   7.7    11.9 (75)
NORTH MELBOURNE     4.5    6.8   9.12  11.16 (82)

GOALS
St Kilda: Riewoldt 3, Membrey 3, Bruce 2, Savage, Weller, Billings
North Melbourne: Brown 2, Petrie 2, Higgins 2, Wood 2, Cunnington, Harvey, Waite

BEST
St Kilda: Riewoldt, Montagna, Newnes, Savage, Geary, Gilbert
North Melbourne: Cunnington, Ziebell, Jacobs, Goldstein, Atley, Tarrant

INJURIES
St Kilda: Riewoldt (knee), Armitage (head knock)
North Melbourne: Higgins (right knee), Wells (corked leg) 

Reports: Nil 

Umpires: Stevic, Kamolins, Hay 

Official crowd: 27,254 at Etihad Stadium