MIDFIELDER Joel Corey is confident Geelong can shake off Friday night's heartbreaking four-point qualifying final loss to St Kilda and keep alive its dream of winning a third flag in four seasons.

Corey was one of many players who started slowly in the game against the Saints, but he finished with 22 possessions as the Cats rallied from 33 points down to almost pinch a famous victory.

The Cats now face the reality of a sudden-death semi-final against either Fremantle or Hawthorn next weekend.

"You've just got to win," Corey said. "We've just got to do it the hard way now.

"I've got full confidence in the boys. It's not ideal, but this is what we have to do.

"We know that if we play the style of footy we did in the second half, for four quarters, we can actually win a game of football."

The 28-year-old, who has missed the bulk of the season due to knee problems, blamed a poor first half for the Cats' upset defeat.

"We didn't really start playing, I guess, until we fell behind and you don't win games of football like that," Corey said, before acknowledging St Kilda's pressure had forced the reigning premier to make many uncharacteristic errors.

Such was the effectiveness of the Saints' game plan that the Cats at times found it almost impossible to clear the ball from their backline.

"[St Kilda] like to squeeze up and play the game in their half and we played into their hands a little bit by not playing on and taking risks," Corey said.

But the Geelong players took plenty from their gutsy effort after half time.

"We started to play. We started to drive at the footy and outnumber them at the contests," Corey added.

"These are the things we weren't doing in the first half when we were quite stagnant and flat-footed.

"We got on the move and things started to happen."