The Pies had their noses in front by a goal in the dramatic final moments of the game, but the Saints had the opportunity to draw level with one final forward thrust.
Relive Saturday night's tense finish on CTV.
After gaining possession, St Kilda was about to go deep inside its attacking 50, but ran out of time as Ben McEvoy was sent from the ground with the blood rule.
The final siren sounded just as Justin Koschitzke's long kick sailed toward a waiting pack - the Pies hanging on to the six-point win, 12.19 (91) to 13.7 (85).
The Saints were also unlucky to score seconds earlier, when a controversial free kick, awarded to Collingwood's Harry O'Brien, robbed them of a scoring opportunity.
It was a fitting end to the see-sawing clash.
St Kilda bounced out to an early lead with Ahmed Saad capitalising on the Saints' superior pressure and run through the middle of the ground with two first-quarter goals.
But their early 13-point lead was whittled back to a four-point advantage at the first break after Darren Jolly, who played one of the best games of his career, drifted forward to kick his first goal of the night.
The Pies lifted their intensity in the second term, with prime movers Dane Swan, Steele Sidebottom and Dayne Beams making the most of the excellent tap work of Jolly.
Collingwood slammed through the first four goals of the quarter to wrench back control of the contest with David Armitage's goal St Kilda's only major for the quarter as the Pies took a deserved 27-point lead into half-time.
But the Saints were able to recapture their early intensity after the break with Brendon Goddard, Nick Dal Santo and Leigh Montagna important around the stoppages where St Kilda won the clearance count 15-6 in the third quarter.
Stephen Milne threw off his early lethargy to boot two goals with Koschitzke's big mark inside the last minute of the term allowing him to put his side back in front by four points at three-quarter time.
Goals to Chris Dawes and Swan were answered by Milne, who bobbed up with his third, but Dale Thomas provided one of the highlights of the match with a brilliant one-handed pick up and goal at full pace.
Saad kept his side in it with a long bomb, but as the Saints pushed for the win, O'Brien was awarded a contentious free kick with 15 seconds remaining, which he put out of bounds on the full to set up the stunning finale.
Collingwood 3.3 8.11 9.14 12.19 (91)
St Kilda 4.1 5.2 11.6 13.7 (85)
GOALS
Collingwood: Jolly 2, Dawes 2, Swan 2, Thomas 2, Wellingham, Fasolo, Cloke, Beams
St Kilda: Saad 4, Milne 3, Dal Santo 2, Riewoldt 2, Armitage, McEvoy,
BEST
Collingwood: Jolly, Beams, Swan, Thomas, Pendlebury, Sidebottom, Shaw
St Kilda: Goddard, Dempster, Hayes, Saad, Montagna, Fisher
INJURIES
Collingwood: Tarrant (soreness) replaced in selected side by Brown, Goldsack (ankle)
St Kilda: Nil
SUBSTITUTES
Collingwood: Tyson Goldsack (ankle) replaced by Tom Young in the third quarter
St Kilda: Dean Polo replaced by Sam Dunell in the third quarter
Reports: Nil
Umpires: Farmer, Margetts, McInerney
Official crowd: 57,873 at the MCG
The views in this article are those of the author and not necessarily those of the AFL or its clubs.
