The Kangaroos were made to look second-rate by the on-song Saints for long periods of the match which Scott said could prove pivotal to his side's season.
"I said to them after the game, 'It's a defining point'. Which way they go, I'll be watching very, very closely," Scott said.
"Obviously we're devastated with that. That was unacceptable and just a really poor performance on all fronts. We were comprehensively outplayed by a team that's in a position we want to be in. It's unacceptable, everyone at the club knows that and we won't stand for that, so I'll be very interested to see how we respond next week.
"We know where we're going as a footy club and we're very confident in the direction we're headed, but today either can be a blip on the radar and an aberration or it can be a defining moment for where we want to go as a club. We'll find that out sooner rather than later."
Following on from the poor start that condemned them to a round one loss against Port Adelaide, the Roos were blown out of the water early by St Kilda, but Scott wasn't interested in looking for trends.
"Bad football is bad football - it doesn't matter if it occurs in the first quarter, the second quarter or whenever it occurs," he said.
"We just had too many lapses and, like all good sides do, they make you pay and they punished us for our poor football tonight."
While the size of the margin was clearly a bitter pill to swallow, Scott was at least consoled by the experience gained by some of his youngsters.
"We're getting quality games into [our young] players on their very good players," he said.
"We're not putting Jack Ziebell in the back pocket, we're not putting Ryan Bastinac in a forward pocket for a whole game. Lachie Hansen isn't playing third or fourth defender - he's playing on the best.
"These aren't just games into young players; these are our go-to players. We rely on those guys."
Skipper Brent Harvey, who has been dealing with the recent loss of his grandmother, was kept to five possessions and got reported on the night, but Scott backed him to lead the response from Arden Street.
"Boomer's had an extremely emotional two weeks," he said.
"Tonight I think like he felt like he had the weight of the world on his shoulders and on top of that Clinton Jones is one of the best defensive midfielders in the competition.
"He needs support around him, but he's a champion, Brent Harvey. I'm not concerned about Brent Harvey in the slightest - he will bounce back from this. It's happened to him before and he'll do what champions always do - they bounce back."
