Midfielder Georgia Patrikios tallied 28 disposals and Jesse Wardlaw was an imposing figure with six marks, two goals, six score involvements and 16 possessions in St Kilda's 5.5 (35) to 1.6 (12) victory.
Brittany Bonici was Collingwood's best with 27 disposals, seven clearances and nine tackles.
The Saints' finals hopes looked slim after they opened their season with a 1-3 record.
But five consecutive wins have them on the cusp of playing finals for the first time in their history.
Next Saturday's clash with fellow finals contender Carlton (6-3) looms as crucial to St Kilda's top-eight hopes, with matches against ladder leaders North Melbourne (9-0) and the Western Bulldogs (3-6) to round out their home-and-away season.
"We're happy to be five on the trot," Patrikios told the Seven Network.
"We want to play finals. It's a weird one - you don't want to mention it too much, but now we're in a position where we can almost get ourselves there.
"So it's going to be on us and all the hard work we're going to do week to week. We're really pushing to play finals this year."
Collingwood won the inside 50m count 37-20 but lacked a reliable target in attack, with the late withdrawal of No.1 draft pick Ash Centra (calf awareness) telling.
The Magpies' only goal of the match didn't arrive until there was just 15 seconds left in the third quarter, when captain Ruby Schleicher took a strong pack mark before kicking truly.Â
St Kilda lost Charlotte Simpson just minutes into the match after an opponent's head crashed into her mouth as she attempted a tackle.
Collingwood won the inside 50m count 8-3 in the opening quarter, but it was St Kilda who kicked the only goal of the term - via Arianna Clarke.
Wardlaw reeled in a one-handed grab to kick the opening goal of the second quarter, and the margin extended to 16 points by halftime after Charlotte Baskaran soccered through another major.
Remarkably, St Kilda were able to kick three goals to none in the first half despite losing the inside 50m count 19-6.
Wardlaw's four first-half marks proved critical to St Kilda, and she took another mark on the lead midway through the third quarter to extend the margin to 25 points, with Collingwood unable to reel in their rivals in.
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