Casswell was with Walton in Rockhampton when he won the Queensland state championship as a 12-year-old, a rare achievement for a Home Hill player – but never thought he would be where he is now. To be fair, neither did Walton.

These days, Casswell has ATP Tour app notifications turned on for his matches.

“His parents, Ash and Sherry, still live here, and we’re so proud of him,” she said. “Adam’s best weapon is his brain. He never gives in, and will fight and fight and fight, and stay in a game for 15 minutes if he has to.”

Walton – who never represented Australia at Junior Davis Cup or was a particularly outstanding junior – will play his second grand slam match and first at Roland-Garros as a wildcard entrant, without a claycourt lead-in match.

Frenchman Arthur Rinderknech awaits him in the first round.

Walton had to win last week’s Challenger final in Taipei against former world No.49 Illya Marchenko to not only secure his top-100 debut but also make the main draw cut-off for Wimbledon.

The 25-year-old ticked off both, but not before losing the opening set and needing to squeeze past Marchenko in a final-set tie-breaker – after losing his only previous clash with the Ukrainian in lopsided fashion last year.

That triumph meant he had to forgo the chance to play in the ATP claycourt event in Geneva last week.

The way Walton reversed his fortunes against Marchenko was indicative of his rapid ascension since graduating from the University of Tennessee two years ago without a ranking at all.

However, the momentum had already started at that point.

He chose the US college route instead of launching straight onto the professional tour after peaking at No.60 in the 18-and-under boys’ world rankings. That might seem impressive, but the strike rate of junior players with that ranking making it at the next level is quite low.

Walton joined some countrymen at “the Vols” in Tennessee, including Pat Harper, who he won the 2021 NCAA doubles title with, but initially was unsure he would even pursue tennis beyond college.

He improved year after year, to the point he was ranked No.2 in the NCAA in singles – behind only Ben Shelton, the ballistic-serving American who reached last year’s Australian Open quarter-finals – and No.1 in doubles. Shelton, who is four years younger, is No.15 in the world these days. For the record, Walton boasts a win over the American star in a UTR tournament, and took a set off him in two other close battles.

“I felt like I wasn’t ready to play pro tennis [after juniors], so going to the US was the right decision, but it wasn’t an easy one because it meant going to the other side of the world,” Walton said.

“I took the leap, and it was the best decision I ever made. I was on line four [the No.4 player] for the No.44 team when I was recruited, but our team progressed a little bit every year, as I did as a player, and by my third year, I was playing No.1, and we were top 15 in the nation. We were a top-five program in my last two years, and we got to No.1 at one stage.”

Tennessee’s head coach, former world No.29 Chris Woodruff, convinced Walton he would regret it if he did not at least try to make it on the professional tour, so the Australian took another chance.

Walton breezed through the Futures circuit – the sport’s third tier – and soon graduated to ATP Challenger level. By August last year, he won his maiden Challenger title in North Carolina, as he morphed into a more aggressive version of the player who excelled at college, relentlessly returning balls.

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Tennis Australia took notice, bringing him into the national academy and subsidising a coach for him, Andrew Roberts, who also works with fellow Australian Tristan Schoolkate, Walton’s closest friend on tour.

Two more Challenger titles followed this year, including the most recent in Taipei, and his ranking soared. Walton prefers to keep his goals conservative to avoid beating up on himself if he fails to meet them, but has a big opportunity in the second half of the season to make further inroads.

“It feels really good to be in the top 100. That’s every tennis player’s goal,” he said.

“I didn’t know if that was achievable when I started playing pro tennis a few years ago, but I slowly chipped away at my ranking, and started believing it was possible in the past few months.”

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