LOSING some "critical balls" and making some poor decisions under pressure cost St Kilda in the frantic final stages of Sunday's seven-point loss to North Melbourne, coach Alan Richardson says.

The Saints almost pulled off an amazing comeback victory from 26 points down at the 10-minute mark of the final term, leveling the scores but just failing short of being the first team to knock-off the undefeated Roos.

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Although Richardson was full of praise for his team's barnstorming finish, the frustrated senior coach also lamented some costly errors in the dying stages – including a kick-out to the pocket instead of up the middle by Sam Gilbert.

"They won a couple of critical balls," Richardson said of the frenzied final minutes.

"We would rather go long up the middle on point kick-in, so that was disappointing.

"We all know what we need to do there, (it was) a bit of a brain-fade there by Gilbo, who I thought had been outstanding on the night.

"He was probably our best player, Gilbo."

The Saints moved the ball to the wing from Gilbert's kick-out, but it quickly came sailing back and allowed Mason Wood to become the hero for North.

Wood caught Jack Newnes holding the ball with 22 seconds left and simply stood and watched the 30-second shot clock tick down, knowing the Roos had the match in the bag.

Five talking points: St Kilda v North Melbourne

The chain of play started with a controversial free-kick awarded to Todd Goldstein against Tom Hickey, who was judged to have shepherded the big Roo at a ruck contest.

Although Goldstein subsequently kicked the go-ahead point for North from 55m, Richardson didn't blame the umpire's call.

"I haven't seen it back. It looked like it was a significant push, it could've just been really good body work," Richardson said.

"It was frustrating because we'd been coming pretty hard and it was a really important moment.

"But it's not as though I know and I'm sitting here and trying to protect the umpire, I actually don't know. It looked like he was in reasonable position and was propelled forward, so who knows?"

The Saints' fightback was inspired by the tireless skipper Nick Riewoldt, who was once again best-on-ground with 24 touches and three goals.

The 33-year-old is close to inking a new deal to play on next season after being "invigorated" by the progress of St Kilda's younger players.

Watch Alan Richardson's full post-match press conference

"That positive performance by some of these young guys coming through has certainly got our skipper excited and wanting to be part of that," Richardson said.

Riewoldt pulled up sore late but the coach was confident the star veteran would be fine to face West Coast in Perth, while he said gun onballer David Armitage was only a "bit dazed" by a head knock.

"He got a bit of a whack. He's got a hard head Dave, so it surprises me that he went out (of the game)," Richardson said.

"They're not calling it concussion, he was just a bit dazed, so the doctors saw fit to get him out of the game halfway through the last quarter.

"It was frustrating but we'll never take risks with players, particularly with head knock … where there's a bit of grey or a bit of uncertainty."