The night before the Mariners' TAC Cup clash against the Eastern Ranges four weeks ago, Webster's family home in Mangalore, a small country town 32km north of Hobart, burnt down.
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Coach Adam Sanders spoke to the 17-year-old and told him to sit the game out if he didn't feel like he could play. Instead, he produced a "captain's performance" against a much stronger opposition.
"I think it was a massive tick in the box for his character," Sanders told AFL.com.au ahead of the Mariners' opening match of the championships, against Western Australia in Launceston on Sunday.
"I certainly think the other boys in the academy respect him even more for the way he went about it during that time."
Zac is the brother of second-year St Kilda half-back Jimmy Webster, who made his AFL debut 10 days after the family tragedy and has held his spot since.
Sanders was also involved in Jimmy's progression through the Tasmania development academies and said nothing much fazed the brothers.
As footballers they are different, but Zac is starting to show the class that will catch the eye of AFL recruiters through the national carnival.
"Jimmy's a fairly polished left footer, whereas Zac's more of a bull-at-a-gate type player," Sanders said.
"He's a real goer, he'll put his head over the ball and he's got great courage. They're great attributes to have, but as we know at AFL level they've got to have class as well.
"I think he'll show that he can be that really polished player as well as a courageous player."
Webster has played most of his football as a half-forward, but he will be used through the midfield and as a half-back during the championships.
Sanders said the change of roles would give him an opportunity to showcase his speed and agility.
"I really like his run and carry and his ability to be able to sidestep and keep running … playing a little bit more behind the ball at times he can show that," Sanders said.
"He plays half-forward quite well because he's very courageous, but what ends up happening is he's on his hands and knees a lot.
"We think he's got a lot more class to be able to be on his feet more.
"We think he's got good kicking skills, which he sometimes can't show because he's always at the bottom of the pack."
Webster, who is on the radar of AFL clubs, has an opportunity to climb up the pecking order if he can showcase his class during the championships.
The view of recruiters is he is less skilful than his older brother, but his toughness, pace and ability to win contested ball are seen as significant strengths.
"Hopefully he does get an opportunity at AFL level, and it might be as that small defender type player," Sanders said.
Nathan Schmook is a reporter for AFL Media. Follow him on Twitter: @AFL_Nathan
