Geelong have been left to dwell on an opportunity gone begging after letting a guaranteed top-four spot slip with an upset 18-point loss to St Kilda.
After Brisbane's one-point loss to Collingwood earlier on Saturday, the Cats only needed victory to seal a double chance in September - and they led by 33 points at half-time.
But an extraordinary third quarter, where St Kilda kicked six unanswered goals and seven to Geelong's one, got Ross Lyon's charges back in the game.
The Saints then seized control in the final quarter to prevail 16.11 (107) to 14.5 (89) in front of 31,945 fans at Marvel Stadium.
It was St Kilda's fifth win in seven matches.
Geelong (56 points, 14-8) sit fourth, just two points ahead of Brisbane, and will need to beat West Coast at GMHBA Stadium next Saturday to lock in a top-four berth, while a home qualifying final has likely gone begging.
"Oh, they're (the players) not morons and the missed opportunity bit - clearly we're disappointed. We knew what was at stake," coach Chris Scott said.
"They just blew us out of the water early (in the second half) and had the momentum. It was really hard for us to stop.
"And they played some scintillating footy. It was kind of Harlem Globetrotters there at one stage, which is unusual, because the first half was so clearly on our terms."
Saints skipper Jack Steele (28 disposals, two goals) and Rowan Marshall (28 disposals, 21 hitouts) were crucial to St Kilda's resurgence.
Josh Battle largely kept Jeremy Cameron (three goals) quiet, while Callum Wilkie (28 disposals, 15 marks) was excellent.
Jack Higgins (three goals) and Darcy Wilson (two goals, 25 disposals) popped up at crucial times.
Lyon indicated a midfield response was behind the turnaround.
"We thought early our pressure and all that was good, but we lacked composure with the ball," Lyon said.
"We were a bit fidgety with it and turned it over - as they do, they make you pay really quickly.
"We come out in the third quarter, we got some momentum out of the middle ... and then our ball use just continued to blossom.
"It was a little bit solution based (at half-time), but it was also 'the team needs you to lift', and to their credit, they lifted.
"So when you challenge people, they need to respond. And they responded, and that shows good footy character."
Bradley Hill (back tightness) was substituted late, while Anthony Caminiti suffered a shoulder injury.
Mitch Owens (two goals) could come under scrutiny after catching Tom Stewart high midway through the final term.
Classy Cats defender Lawson Humphries (24 disposals) stood out, while Jack Bowes (31 touches) and Shaun Mannagh (two goals, 21 touches) impressed.
Geelong kept the Saints goalless in the first term and kicked the first four goals of the game.
But the Saints snared four unanswered goals, including two to Wilson, inside the opening five minutes of the third term.
Tim Membrey kicked St Kilda's fifth on the bounce to level the scores, before Higgins gave the Saints the lead.
St Kilda led by six at three-quarter-time, and while the final term initially proved an arm-wrestle, five consecutive Saints goals put the game to bed.
The Saints (13th, 10-12) finish their season against Carlton next Sunday.
