Geelong have pipped Sydney by 12 points in a low-scoring AFL thriller at the SCG, overcoming a case of the yips and an inspired Lance Franklin.
The Cats prevailed 8.23 (71) to 9.5 (59) in one of the stranger games of the year.
The Swans kicked more goals than the visitors -- despite Geelong having more than twice the number of scoring opportunities.
"It's a bit unusual when you see that number of behinds on the scoreboard," Cats coach Chris Scott told reporters.
"It wasn't just the misses. It was the number of entries we were having as well, we were pretty dominant for big parts of the game and just weren't getting the reward.
"It's always a worry ... it added to the tension.
"There were a lot of rushed and low percentage shots we took, so it's not as if we missed a whole lot of sitters."
The Swans' loss means they will slip out of the top four if Port Adelaide defeat St Kilda on Saturday.
It could also prove incredibly costly on the injury front, with veterans Kieren Jack (knee), Jarrad McVeigh (broken collarbone) and Dan Hannebery (calf) all suffering knocks.
Geelong's inaccurate goal-kicking and Franklin's four goals meant the contest was in the balance at three-quarter time, with the scores level.
Patrick Dangerfield converted a set shot after a contentious free kick to put the visitors in front some two minutes into the final term.
They never relinquished the lead, despite Tom Hawkins and Jamaine Jones both missing chances to land the knockout blow.
Hawkins registered three behinds in the final quarter, including a set shot from in front, before Tim Kelly snapped the sealer on Thursday night.
"Tim Kelly stepped up tonight. What a moment and what a player. Someone in their first year, taking it upon himself to finish the work," Cats captain Joel Selwood told the Seven Network.
Geelong's victory, coming after losses to Richmond and Western Bulldogs, ensures they will stay in the top eight.
Franklin fell one goal short of booting the 900th goal of his career.
The superstar was one of few Swans to stand up in the lopsided opening half, tormenting opponent Mark Blicavs with a couple of classy goals.
Franklin then kicked the opening two goals of the third quarter, but the Cats rallied.
Swans coach John Longmire lamented how his team were "smashed out of the centre", also pointing to the lack of quantity and quality when it came to their forward entries.
"There's a few things there we need to get better at. Regardless of personnel, we can certainly control a few of those things better than we have been," Longmire said.
Geelong midfielder Mitch Duncan was among the leading best-on-ground contenders, tallying 32 disposals, while Kelly, one of five players to debut for the Cats this year, kicked two goals and showed great composure throughout the match.
Hawkins, who helped push his side's lead to a match-high 21 points during the second term, finished with 2.5.