Hobbled superstar Lance Franklin's six-goal haul and a stunning match-winner from Tom McCartin have dragged Sydney back into the AFL's top eight, with the Swans pipping Collingwood by two points at the SCG.
Franklin defied a restrictive heel injury, which has prevented him training this season, to boot three goals in the first quarter then ignite a third-quarter fightback.
The Swans triumphed 11.7 (73) to 10.11 (71) on Saturday night, when Darcy Moore became the latest victim in the Magpies' injury-cursed season.
The Swans, down by 17 points at the major break and fearing a defeat that would all but ensure they miss finals for the first time under John Longmire, sparked to life and held a 18-point lead when Franklin slotted his sixth goal about 17 seconds into the final term.
The Magpies, who were without Moore for almost three quarters because of a suspected hamstring injury, rallied in style and reclaimed the lead when Travis Varcoe kicked his fourth goal of the night.
Franklin hit the post, for the third time in the low-scoring arm-wrestle, before McCartin somehow got boot to ball at the bottom of a pack to kick a scrubby goal with two minutes remaining.
A frantic series of smothers, spoils, tackles and kicks under immense pressure followed, with Isaac Heney holding a clutch mark in defence to defuse the visitors' final foray forward.
"It was a tough game of football. We had to find a way to win the game, backs against the wall. I couldn't be more proud of the boys," Franklin told the Seven Network.
"I was beaten the last two weeks, convincingly. I wanted to bounce back."
The Swans next face Melbourne at the MCG before tackling GWS and Hawthorn in a tricky run home.
"It's going to be a tough three weeks but we're excited by it," Franklin said.
Collingwood ruckman Brodie Grundy produced arguably the highlight of his stellar season, helping himself to 57 hitouts while generating nine clearances, but couldn't drag his side over the line.
"It was the type of night where a scrambling goal was likely to make the difference. It did," Magpies coach Nathan Buckley said.
"We played three quarters, you can't afford to do that against a good opposition. The third quarter was really poor."
The Swans kicked five goals to zip in the third term, turning the game on its head.
With Franklin's first opponent Moore unavailable, debutant Jack Madgen often had the job on the four-time Coleman medallist during the second half.
Swans coach Longmire was full of praise for Franklin but also defender Alex Johnson, who played his first AFL game since the 2012 grand final.
"He played an important role and helped us," Longmire said of Johnson, who manned giant American Mason Cox in his comeback game after five knee reconstructions.
"I'm glad we had our noses in front at the final bell."