Konstas will become the youngest Australian ever to play Test cricket at the SCG on Friday, a week after the 19-year-old's captivating debut in Melbourne.
A close confidant of Konstas for the past four years, Watson admitted on Thursday even he was surprised how the opener took on Jasprit Bumrah in Melbourne.
But he was confident there was a method to Konstas's madness, after the opener attempted to scoop Bumrah five times and then began charging the quick.
Konstas played and missed his first two scoop shots, before hitting the Indian star for three boundaries in the one over during his first hour of Test cricket.
"I understood what his game plan was, or what plan A was anyway," Watson said.
"So when plan B kicked in quite quickly, within a couple of overs, that was a little surprising.
"But the one thing that we've always talked about is trusting his gut."And obviously after those first couple of overs of Bumrah, he felt 'if I just bat normally it's a matter of time before he gets me out'.
"So he obviously just went with what he felt and fully committed to it. And that takes a lot of courage."
India responded in the second innings by putting two men deep behind the wicket, putting Konstas at risk of being caught in the deep if he played the scoop.
But Watson said his protege would have no issue putting the shot away, having played a more traditional red-ball game throughout his rise in Sheffield Shield this year.
Sam Konstas (pic) can also be technically correct, says his batting mentor Shane Watson. (Dan Himbrechts/AAP PHOTOS)
"He's going to have to tap into different aspects of his game, but he is technically very correct," former Test opener Watson said.
"He can certainly just stand there and bat normally and wait for loose balls, but he's also got the other gears to be able to hit the ball down the ground.
"His blueprint will be a balance of all his shot options that he's got. It will certainly be putting the pressure on the bowler."
Konstas was inundated with ticket requests this week, having only attended SCG Tests and lining up for David Warner's autograph a few years ago.
He has also made the choice to stay in the team hotel, while most players sleep at home during their own city's Test.
But his youthfulness was still on display at Wednesday's Prime Minister's function, wearing black sneakers with his suit, days after his exuberant interaction with the MCG crowd.
"My experience of dealing and working with Sam has been a very quiet, reserved personality. (He's a) very deep thinker and certainly not an extrovert," Watson said."But obviously what we saw in the Test match is that he absolutely is a showman and wasn't overawed."