Sydney’s AFL league-leading defence are determined not to be caught out again by a St Kilda team presented with a unique opportunity on Sunday.

The vagaries of the draw mean the Saints are the only team in the competition with a chance of winning two regular season games against the Swans this season.

Adelaide and Richmond, the only other clubs to have beaten Sydney this year, won’t get another crack at the Swans unless they meet them in the finals.

The Saints go into Sunday’s SCG encounter after back-to-back wins but haven’t posted three successive victories this season.

They already boast a 28-point win this year over Sydney, but will almost certainly surrender eighth spot with a loss at the SCG.

Since dropping their colours to the Saints, Sydney have won their past six games to surge to the top of the ladder.

Swans coach John Longmire has talked up the Saints at very opportunity, even referring to the squad named for Sunday’s game as the “who’s who of grand final footy.”

The 111 points the Saints scored against Sydney was the highest conceded this year by the Swans, who have allowed a league-best average of just 70 per game.

“We just let ourselves down a bit against St Kilda last time and there’s definitely a few things that we’ve got to improve on,” Sydney back Nick Smith told AAP.

He stressed the responsibility for shackling the Saints potent offence wouldn’t just rest with Sydney’s back six.

“It’s going to come down to a team performance,” Smith said.

“I don’t think it’s just up to the defenders to defend.”

Earlier in the season, Smith had the job on champion forward Stephen Milne, who on Sunday will make his 252nd appearance for the Saints.

That will move Milne alongside Justin Peckett into equal eighth on the club’s all-time games list.

“I’ll rely on the midfield helping out as well to be able to defend him, so my work will be cut out that’s for sure,” Smith said.

“He doesn’t need much of an opportunity to kick a goal, he can kick them from anywhere, just a really clever player.

Sydney are unchanged, while Saints regain Brendon Goddard and Jack Steven from suspension in place of Farren Ray and Beau Wilkes.