The Suns played most of the final quarter with no-one on the bench but held on for a gutsy 11.14 (80) to 10.15 (75) victory in front of a Metricon Stadium record crowd of 24,032.
They overcame a poor first half to strangle the Magpies and retain a spot in the top eight.
But Ablett's third quarter injury could send their finals aspirations into a tailspin.
Vote for your top three players from Collingwood's five-point loss in the Magpie Army Player of the Year Award.
Not only did the Suns play the final 50 minutes without their skipper, but also finished the game minus Charlie Dixon (calf), Trent McKenzie (hamstring) and Sean Lemmens (concussion).
The Suns had no rotations for the final 20 minutes but gutsed it out.
"On the back of our skipper being off...and having no rotations late, I don't think it was our best win as far as the way we played, but our most courageous, clearly," Suns coach Guy McKenna said.
"The perseverance and the courage to keep running until the final siren blew was certainly a sign of growing up tonight."
David Swallow (31 disposals) was magnificent, Harley Bennell (26) lifted after a slow first half and Sam Day found form with four critical goals.
His fourth from 55m with just minutes remaining sealed the deal when the Suns were being challenged.
Clinton Young missed a golden chance to put the Magpies in front late when he dropped a simple chest mark 30 metres out with just two minutes left to play.
Ablett's injury will send shockwaves through the competition after he was helped off by trainers in severe pain after falling awkwardly in a Brent Macaffer tackle.
Ablett appeared to break his fall with his left elbow, forcing the shoulder out of place.
McKenna said he would have scans on Monday to determine the amount of time on the sidelines.
The champion had racked up 19 disposals before his injury, which came just minutes after Dixon was subbed off with his corked calf. Coach Nathan Buckley said the Magpies lacked composure as the match wore on.
"We had fit men on the bench but you only play with 18 on the field," he said of the Suns' lack of numbers.
"They were able to keep going. Their contested ball was good. They still had the ability to power into and out of the contest through that second half in particular, and we couldn't match it or better it.
"We clearly controlled the game in the first half and didn't maximise our opportunities. It's poor footy if we don't take advantage of those opportunities."
Collingwood were brilliant in the opening term and settled much quicker in front of the near sell-out crowd to lead by 13 points.
Travis Cloke caused all sorts of headaches early, and after kicking 1.2 and giving off two goals to Clinton Young, forced Suns coach Guy McKenna to shift Steven May and put Rory Thompson on the star forward.
In the second quarter Collingwood kept the pressure on, but somehow the Suns reduced the lead to 11 points at the main break.
The visitors had a run of 10 straight behinds during the second and third quarters to kick themselves out of the match.
Gold Coast 2.2 5.3 8.7 11.14 (80)
Collingwood 4.3 6.8 6.13 10.15 (75)
Goals - Collingwood: Young 2, Cloke 2, Kennedy 2, Sidebottom, Goldsack, Thomas, Seedsman
Gold Coast: Day 4, Lynch 2, Dixon 2, Hall, Bennell, Prestia
Best - Collingwood: Pendlebury, Cloke, Witts, Beams, Kennedy
Gold Coast: Swallow, Day, Rischitelli, Bennell, Lynch
Injuries - Collingwood: Nil
Gold Coast: Ablett (shoulder), Dixon (calf), McKenzie (hamstring), Lemmens (concussion)
Substitutes - Collingwood: Josh Thomas on for Sam Dwyer in the third quarter.
Gold Coast: Alex Sexton on for Charlie Dixon in the third quarter.
Reports: Nil.
Umpires: Nicholls, Ryan and Mollison.
Crowd: 24,032 at Metricon Stadium.
