Saturday night's 12.12 (84) to 8.9 (57) win puts the Cats eight points clear at the top of the AFL ladder and fully extinguishes any slim hopes the Saints had of playing finals this season.

Faced with the daunting task of taking on the ladder-leaders at their home fortress, the Saints fought valiantly and took the lead during the second quarter.

But the Cats wrestled the game back onto their terms after halftime, Gary Ablett snagging two late goals in quick succession to put the result beyond doubt.

The Geelong champion had looked proppy for much of the game after copping a knock to the hip in the second quarter.

"I'm not exactly sure how he's pulled up. He was limited," Geelong coach Chris Scott said of Ablett.

"The fact that he stayed out there is a really good sign ... I thought he was pretty important in the last quarter."

Fellow stars Patrick Dangerfield (32 disposals, one goal) and Mitch Duncan did most of the damage with Saints tagger Jack Steele managing to subdue Tim Kelly.

Key forward Esava Ratugolea slotted two majors on his return from a hamstring injury.

While the Saints averted what had loomed as a potential blowout, another loss can only spell bad news for besieged sixth-year coach Richardson.

In the past 11 rounds, the Saints have won just twice - against lowly Gold Coast and Carlton.

St Kilda football boss Simon Lethlean declared last month the Saints needed to show clear improvement for Richardson to remain coach beyond this season, stressing that this meant beating teams above them on the ladder.

Four straight losses to Brisbane, Richmond, North Melbourne and now Geelong have left Richardson's position virtually untenable.

Saints fans at least got a glimpse of a brighter future with ruckman Rowan Marshall (31 hitouts, 21 disposals and a goal) among St Kilda's best while fellow youngsters Hunter Clark, Ben Long and Callum Wilkie were also impressive.

"There was some real frustration for us given that the effort was so strong and the execution of the plan was where it needed to be," said Richardson, who would not be drawn on his job security.

"We just let ourselves down with our use."

The Cats had the run of play in the early going but St Kilda ramped up their intensity in the second term.

Josh Bruce went back with the flight and was crunched in a contest that brought the ball to ground and set up Jack Lonie's crumbing goal.

Rowan Marshall laid out Geelong forward Luke Dahlhaus with a hip and shoulder shortly after kicking truly from a soaring mark.

And when Ben Long ran down Zach Tuohy and drilled his set shot from 45m, the Saints had four straight goals and held a 10-point lead.

But the Cats found another gear and dominated from there to reassert their status as premiership favourites.

Australian Associated Press