Carlton's 16.14 (110) to 10.14 (74) win brings its record to 7-8, a game adrift of the floundering Port Adelaide, well beaten by Hawthorn at AAMI Stadium earlier in the day.
North Melbourne and West Coast are also in the logjam for what shapes as the only remaining berth in the finals.
The difference between the Blues and the Saints on Saturday was their respective key forwards. In the absence of the injured Jarrad Waite, Lachlan Henderson kicked four goals for Carlton and Sam Rowe chipped in with three.
At the other end, first year St Kilda forward Tom Lee kicked three goals, but that was it. Saints skipper Nick Riewoldt presented well – as always – but was wayward with the ball, kicking 1.4.
It was a chippy game. There was a wrestle involving several players before the opening bounce and scuffles throughout, although nothing on the field was directed towards Saints small forward Stephen Milne, who was playing his first game since being charged with four counts of rape last month.
Milne was booed lustily by the predominantly Carlton crowd throughout. He kicked two goals in the third term to get his side back in the game but otherwise was well held by Zach Tuohy.
The inaccurate Saints led by three points at the first change, but Carlton took control of the match for good in the second term, with a four-goal burst in five minutes from the five-minute mark of the second term that turned an eight-point deficit into a 17-point lead.
St Kilda would never get closer than eight points thereafter, and while it was in with a sniff at three-quarter time, trailing by 11 points, Carlton slammed the door shut with five goals to one in the final stanza.
The Blues were well led by Kade Simpson (28 possessions off half-back) and Chris Judd with 26 touches. Bryce Gibbs (20), Marc Murphy (20) and Jaryd Cachia (20) were also industrious for the Blues.
Also meritorious for the Blues was Ed Curnow who had 16 possessions while curbing St Kilda's Leigh Montagna, who ran riot with 11 possessions in the first quarter but garnered just 11 thereafter.
St Kilda's best was Lenny Hayes with 27 touches. Farren Ray had 26, while David Armitage had 25 possessions. But Armitage could be reported after a clash with Rowe in the final quarter.
The win was only Carlton's third from its last 19 outings against St Kilda, a record coach Mick Malthouse suggested might have become a "burden" for his players.
"The Saints have been good. Have they bullied us? Have they been too good forward, too good back, too good in the midfield? The significance of getting out there and winning the game automatically lifts part of that burden," he said.
Saints coach Scott Watters said the game mirrored many others in in the club's three-win season. "Our effort in the contest is pretty honest, but our ball use and our efficiency requires some work," he said.
Both clubs are back at Etihad Stadium next weekend. The Blues play North Melbourne in a crunch game on Friday night, while the Saints host the desperate Port Adelaide on Saturday night.
