Knights, who said he rated the Saints as "pretty close" to last year's grand finalists Geelong, said the Bombers will focus on contested situations this week in the lead up to the round eight match.
"We'd have to match them in that area, or go close to matching them," he said on Tuesday.
"When we played at the Gabba against Brisbane, they towelled us and completely obliterated us in the contested ball, and against Hawthorn we were able to match players like Brad Sewell and Luke Hodge on the inside, where they're so good.
"We're still very indifferent in [contested possessions] so we've got to make sure we pay attention to that during the week in our meetings and training and get that side of our game to evolve."
Knight said he was impressed by the Saints' convincing display against Collingwood on Monday night at Docklands, and believed they had taken their game to a new level this season.
"I saw them from about 90m away and they looked very strong. Their form line in the first part of the year has been impeccable," he said.
"I think they're pretty close to the Cats, I really do. The Cats are a super team but the Saints are making ground and I guess you can only tell when they run up and clash against each other.
Knights said he would back young defender pair Cale Hooker and Tayte Pears, who have played 14 games between them, to take on St Kilda's twin towers Nick Riewoldt and Justin Koschitzke after showing promise against the big Hawks last Friday night.
"There's not much other option there," he said with a laugh.
"They got the gigs last week against Roughead and Franklin, and they're probably a good chance to get the gigs again because that's where we're at.
"[Michael] Hurley is still coming back through the VFL and Dustin [Fletcher] is still two or three weeks away.
"I don't mind throwing challenges to young players and they did it admirably last week ... We'll probably throw similar challenges to them this week and they've just got to play hard and aggressive and I'll back them in to do the job."
