The Kangaroos dominated territory (67-51) and generated more shots than the Swans, but were on the wrong end of a 16.9 (105) to 14.13 (97) scoreline at Marvel Stadium on Saturday.
The hard-fought contest was still alive in the final minute when a flying attempt at goal from North's Cam Zurhaar floated the wrong side of the post.
The result meant Sydney (8-1) reclaimed top spot from Fremantle on percentage, while the Kangaroos (4-5) sit just outside the wildcard positions as they seek to end a decade-long finals drought.
"We're taking confidence and belief out of the fact that we're challenging hard, but we just need to be in these situations more often against high-quality sides so that we can learn to play the moments just a little bit better," North coach Clarkson said.
"At the minute, those sides are on top of the ladder or close to it because they have had experience managing those moments a bit better than us at the present time.
"But we'd like to think we're going to get better at that as we have more experience in those types of games."
The Swans were well served by Isaac Heeney (24 disposals, seven clearances) and Nick Blakey (26 touches), while Chad Warner (18 disposals, one goal) shifted forward to have an impact.
Hayden McLean and Logan McDonald kicked three goals each in the absence of fellow tall forward Charlie Curnow (abdomen), Heeney also booted three and Tom Papley provided a spark with two.
At the other end, third-gamer Will Edwards kept North skipper Nick Larkey (0.2, eight touches) goalless.
Despite logging a sixth consecutive win, Sydney coach Dean Cox felt there was plenty of room for improvement.
"We weren't able to defend the ground as well as we have," Cox said.
"We allowed that (transition) a little bit too often and gave them some looks. To their credit, they took that opportunity.
"From a coach's perspective you understand you're never going to get perfection in any area of your game, but you've got to be as balanced as you possibly can through your defence, your contest work and your attack.
"I suppose today we fluctuated between those three too often."
Luke Davies-Uniacke (34 disposals), Luke Parker (29) and Harry Sheezel (31) fought hard for North, who led by 19 points during a six-goal first quarter and never trailed by more than the same margin.
Finn O'Sullivan, Jack Darling and Zane Duursma kicked two goals each for the Kangaroos.
O'Sullivan took a huge mark in the goal square and converted his set shot late in the final term, drawing North back within two kicks, but the Swans hung on.
North's gallant performance came as the club celebrated the 30-year anniversary of their 1996 premiership, with Wayne Carey among the former stars in attendance
The result was Sydney's 11th consecutive win over the Kangaroos, continuing a run of dominance that started in 2018.
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