The Roos 10.4 (64) defeated the Saints 8.11 (59) to record their sixth win of the season, and their second in the past three rounds.
After North Melbourne led at every change, the Saints hit the front for the time when Andrew McQualter wobbled through the first of the last quarter. Justin Koschitzke then added his third and the Saints were up by seven points.
Just as the pendulum was starting to swing St Kilda's way, Petrie answered with his third.
And when Josh Smith's shot at goal sailed through for a behind, the scores were level at the 18-minute mark.
Another score was not registered until red-time and it came through Drew Petrie, who kicked his fourth at the 25-minute mark, after taking an outstanding contested mark when reaching over the top of a pack. His major was the sealer.
St Kilda skipper Nick Riewoldt, who was his side's best, had a shot at goal from outside 50, but it was punched through by North Melbourne defender Nathan Grima and the Kangas held on for memorable victory.
Petrie was outstanding with four goals and eight marks (three contested) and stood up when he was needed the most. Midfielder Andrew Swallow was best over the day, setting the tone with 13 touches in the first term, before finishing with a game-high 33 disposals.
Brady Rawlings had 22 touches at half-time, before finishing with 32 and first-year Roo Liam Anthony (31) was also important.
Levi Greenwood was given the task of running with Brownlow Medal contender Nick Dal Santo and the young Roo did a fine job blanketing the Saint for the entire afternoon.
For the Saints, Riewoldt was outstanding and kept his side in it with three goals and 11 marks.
Jason Gram and Brendon Goddard were strong four-quarter contributors for the Saints and Farren Ray lifted considerably in the second half.
North Melbourne got off to a flyer with it booted the first five goals.
Aaron Edwards and Petrie booted two goals each and when Todd Goldstein kicked truly early in time-on, the Roos were up by 32 points.
St Kilda finally opened its account at the 23-minute mark via Riewoldt. He then quickly followed up with his second and when Koschitzke opened his account, the Saints reduced the deficit back to 14 points at quarter-time.
The first term scenario threatened to play out in the second quarter when Matt Campbell and Leigh Adams kicked the first two goals, giving North Melbourne a 24-point buffer.
Again it wasn't until red-time until St Kilda landed its first – and only – goal of the term, when Riewoldt added his third.
St Kilda was held to its equal lowest half-time score for the season. The only time it booted 4.4 was against the Sydney Swans in round one. Interestingly, the Roos also held the Saints to 4.7 when they met in round 11.
St Kilda upped the ante after the main change, holding the Roos to just two scoring shots as the Saints had two during the third term.
But inaccurate kicking for goal from the Saints resulted in 2.5 to 1.1, meaning the Roos were still in front by six points heading into the final stanza.
Although St Kilda outscored North Melbourne by a point in the final term, the Roos were able to hold off the Saints for just the third time in their past 10 outings.
North Melbourne face Port Adelaide in the final round next Sunday, while St Kilda will attempt to return to its winning ways before the finals against bottom-placed team Melbourne.
St Kilda 3.0 4.4 6.9 8.11 (59)
North Melbourne 5.2 7.2 8.3 10.4 (64)
GOALS
St Kilda: Koschitzke 3, Riewoldt 3, McQualter, Ray
North Melbourne: Petrie 4, Edwards 2, Adams, Campbell, Goldstein, Swallow
BEST
St Kilda: Riewoldt, Goddard, Gram, Ray, Fisher, Gilbert
North Melbourne: Swallow, Petrie, Anthony, Greenwood, Grima,
INJURIES
St Kilda: TBC
North Melbourne: TBC
REPORTS
Nil
Umpires: Stevic, Grun, Keating
Official crowd: 30,522 at Docklands
The views in this article are those of the author and not necessarily those of the clubs or the AFL.
