Geelong coach Mark Thompson admits there is an edge to the intense rivalry with St Kilda ahead of their AFL blockbuster on Sunday.

Cats captain Tom Harley has tried to play it down, but Thompson says there is extra feeling when the two sides play.

Geelong and St Kilda are unbeaten after 13 rounds and this will be one of the biggest home-and-away games in the league's history.

"I don't think we like each other too much," Thompson said.

He adds Geelong will have no trouble with their players being aggressive, provided they stay within the rules.

Cats fullback Matthew Scarlett is likely to receive extra attention from the Saints following his verbal confrontation with St Kilda legend Robert Harvey at the end of last year's qualifying final.

"Matty will be ready for it - he's a really blunt, direct person," Thompson said.

Meanwhile, Thompson says that Geelong are becoming prisoners of their own ongoing success.

The Cats have won 55 of their last 58 AFL games ahead of Sunday's blockbuster against St Kilda and coach Mark Thompson feels it is creating unrealistic expectations among their fans.

Even though Geelong are unbeaten this season, there is some talk about their form ahead of the St Kilda clash.

The Cats failed to win a clearance in the last quarter on Sunday against Port Adelaide, but Thompson said there was no need to push with the game clearly won and a much bigger assignment to follow.

"There's this expectation for people, when they see the Cats play, to have the foot down on the pedal 100 per cent of the game," Thompson said.

"It's impossible to do week after week, quarter after quarter.

"In our minds, it's a little bit acceptable that we just get in games and do enough to win, we don't have to win by 80 points, it's not one of the expectations that we hold.

"It is a bit of an expectation of people who watch the Cats and sometimes they say we were disappointing if we don't just blast a team out of the park in the last quarter - to us, it's not a concern."

The Port Adelaide win followed two close games against West Coast and Fremantle - again, matches Geelong were expected to win easily.

Thompson admits the last term against the Power was not great, but it was enough.

"We didn't do much wrong, except we didn't get the ball," he said.

"We basically put the cue in the rack, we felt, as a team, and we had a pretty disappointing last quarter.

"But again, if you do enough in a game of footy to be in a position where you're going to win, you can't be too critical.

"If we had won the last quarter by eight goals, we maybe would have wasted a bit of energy - the result was there, we were always going to win it and we'll be right for this week's game."

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