The Swans have withstood a fierce second-half challenge from North Melbourne to cement their top-two spot following a 16-point triumph at Etihad Stadium on Saturday night.
Lance Franklin's four majors and a vintage performance from a rejuvenated Adam Goodes propelled the Swans to a 14.7 (91) to 10.15 (75) victory, and back above West Coast on the ladder.
Despite the Roos' endeavour, their season is back on a knife-edge at 5-6 following their third loss in four games.
Goodes bagged three majors from 14 touches, shrugging off the booing of Roos supporters – who ignored Jack Ziebell's appeals to respect the dual Brownlow medallist - to wield a significant impact on the match.
Franklin flitted in and out of the game, but had the better of Scott Thompson, and in typical style stood up to kick the match-sealer in the final minute with a wobbly 55m bomb.
Lewis Jetta and co-captain Jarrad McVeigh were the architects of the win with their damaging kicking from half-back, while star midfielders Luke Parker, Josh Kennedy and Dan Hannebery were influential.
Todd Goldstein continued his stellar season in the ruck, but despite North's hard-working onball division of Ben Cunnington, Andrew Swallow and Jack Ziebell the Roos never hit the front.
The Swans built the hard-fought win on a dominant second term, when they piled on five goals to one to open a 29-point advantage at half-time.
North rallied after the long break and interim coach Darren Crocker's men threatened to steal a huge upset when they finished with all the run after trailing by 20 points at the final change.
The Swans wobbled under pressure, but from six scoring shots the Roos only managed 2.4 to 2.0.
The Roos were left lamenting a crucial missed set shot from 30m by Jarrad Waite at the 21-minute mark, which would have brought them back within a kick.
When the impressive Shaun Higgins dragged his 50m set shot wide with a minute to go the game was just about up.
It was the Swans' sixth-straight win, and John Longmire's men will rest easy over the bye knowing their shot at redemption from a dismal 2014 Grand Final is well on track.
The Roos are stuck in 12th spot on the ladder and in a dog fight just to play finals after again falling short against one of the League's elite teams, having also lost to Hawthorn and Fremantle this season.
NORTH MELBOURNE 3.4 4.6 8.11 14.7 (91)
SYDNEY SWANS 4.3 9.5 12.7 10.15 (75)
GOALS
North Melbourne: Thomas 2, Higgins 2, Nahas 2, Petrie, Harvey, Wright, Dumont
Sydney Swans: Franklin 4, Goodes 3, Tippett 2, Rohan 2, Jetta, Cunningham, Hannebery
BEST
North Melbourne: Goldstein, Ziebell, Cunnington, Hansen, Harvey
Sydney Swans: McVeigh, Rampe, Franklin, Parker, Kennedy, Laidler, Goodes
INJURIES
North Melbourne: Nil
Sydney Swans: Grundy (knee)
SUBSTITUTES
North Melbourne: Trent Dumont replaced Scott McMahon in the third quarter
Sydney Swans: Dan Robinson replaced Gary Rohan in the final quarter
Reports: Nil
Umpires: Shaun Ryan, Ben Ryan, Jacob Mollison
Official crowd: 32,217 at Etihad Stadium
