Watts described his debut Premier League appearance for the Saints in their 3-1 midweek loss to Mikel Arteta’s side as “surreal”.
It’s a feeling the 19-year-old midfielder might become familiar with as coach Ralph Hasenhuttl vests his trust in the would-be Socceroo to help plug the gaps in an injury-hit squad.
Having impressed in the previous week’s FA Cup win over Shrewsbury, the former Joey became only the second Australian to feature in England’s top tier this season during his 18-minute cameo at St Mary’s.
The other, goalkeeper Mat Ryan, was sitting on the Gunners’ bench after arriving on loan from Brighton.
Ryan later texted Watts a congratulatory message and while the London-born and raised youngster professed disappointment at not making a greater impact, he said the occasion would be locked in his memory bank forever.
“I was talking to a teammate afterwards and I was telling him it felt surreal to be out there playing with Willian in front of me,” Watts told The World Game.
“Facing these types of players is what I’ve been dreaming about my whole life.
“It was an incredible experience, despite a frustrating result.
“To get on the pitch against a team like Arsenal is something I’ll never forget.
“I was just glad the manager trusted me enough to throw me on.”
The former Queens Park Rangers junior has already been likened to Aston Villa’s Jack Grealish, and not simply for his propensity to play with socks rolled down around his ankles.
Watts’ game is a blend of industry and perceptive passing glazed with probing runs and quick feet.
He grew up, though, admiring another Jack, the more gritty-than-pretty former Arsenal and England workhorse Jack Wilshire.
On dissecting his debut, it quickly becomes clear that Watts is no braggart.
“I think I could definitely have done a lot better,” he said.
“I gave the ball away once or twice and there was one where I should have shot but I turned, and we won a free-kick.
“But it was good to get that first one out of the way.
“It’s something to build on and I’ll do all I can to try and make an impact whenever I get on the pitch again.”
Watts won’t allow the prospect of being a torchbearer for Australian hopes in the Premier League weigh on him.
“It’s a shame there aren’t more Australians here (at this level) but I’m sure there will be others coming along,” he said.
"I don’t think about it (being a rarity whose every move will be followed).
“I just focus on playing football - the more you buy into things, the more stress it brings.
“For me, it’s now about picking up as many minutes as I can before the end of the year.
“There have been a few injuries at the club, and as a young player you need those on your side to get an opportunity.
“The senior players have been really good to me, and in particular (England international) James Ward-Prowse has been helpful in a game situation especially, telling me what to do. That helps to calm any nerves.”
The son of a doctor, Watts has grandparents in Perth and an uncle, aunt and cousins in Sydney.
He speaks with a London twang courtesy of a childhood spent in the working class suburb of Willesden.
Though eligible for England, he’s hoping to follow up his appearance for Trevor Morgan’s Joeys at the U-17 World Cup in 2019 by joining the Olyroos and Socceroos setups.
“I’ll take it as it comes but I definitely want to play for the senior team and the Olyroos,” he added.
“It’s up to the coaches (Graham Arnold and assistant Rene Meulensteen) on who they think will help their team the most and hopefully I’ll be part of future squads.
“I had a good chat with Rene the other day, and we’ll see what happens.”
Asked how he’d characterise his qualities, Watts replied: “I like to think of myself as an all-rounder.
“There are definitely some weaknesses which I’m working on. But I think I’m quite a good ball carrier and I run in behind quite well.
“But I’ve got to keep working and developing on a lot of levels.
“I’ve always liked the way Jack Wilshire plays... a small midfielder who’s good at everything really.
“I know he’s had injury problems but he’s got a bit of bite about him and is never afraid to stick in a tackle.”
Referring to his own genesis from Sunday league to the Premier League, Watts added: “I’ve had a bit of a funny journey. I joined QPR at eight but got released about two years later.
“I had trials elsewhere and played some Sunday league but then went back to QPR around 13... had some good years there before joining Southampton at 16.
“It’s a club with great facilities. When I first saw their training ground it was like, ‘oh wow’.
“And of course everyone knows about their reputation for bringing players through.”