It was almost amateur hour at the Australian Open in Sydney as golf's future stars announced their arrival on the big stage.
A day after 16-year-old Rachel Lee claimed a surprise share of the first-round lead in the women's event, her fellow Endeavour Sports High graduate Jeffrey Guan shook up the men's order at the dual-gender showpiece.
Guan's six-under-par 66 at The Lakes on Friday rocketed the 19-year-old prodigy some 49 places up the leaderboard into a tie for seventh in his daring bid to steal the Stonehaven Cup from some of the game's biggest names.
"I actually didn't know that. It was good to get my game sort of sorted these past couple of weeks," Guan said after being told he'd charged into the top 10.
"I actually hit 18 greens today, which helped. I left a couple of putts out there on the front nine but other than that I played all right."
Guan, who only turned professional a month ago, is beautifully placed for a weekend assault at The Australian, his home track where the precocious talent won the club championship as a 14-year-old in 2018.
Guan's emergence as a contender is no great surprise to superstar Cameron Smith.
"He's a great golfer," Smith said after finishing three shots behind the teenager at four under through the Open's first 36 holes.
"He plays out of here as well and he's really comfy around here.
"He's one of those guys that has continued to improve and I can see him being a really good player in the future."
Guan is also backing a trio of young-gun amateurs threatening to upstage the established stars in the women's Open.
Despite Lee falling from contention with a second-round 79 at The Australian, Queenslanders Justice Bosio (19) and Sarah Hammett (16) and South Australia's Caitlin Peirce (21) all made moves.
Bosio and Hammett are in the Golf Australia high-performance program, and they proved their bona fides in style.
A four-under 69 at The Lakes meant Bosio finished the day in outright fourth, while Hammett and Peirce are one stroke back in joint fifth after shooting rounds of 71 and 69 respectively at The Australian.
Bosio has been runner-up in the Australian amateur championship for the past two years, while Hammett won 2022's NSW amateur title on the same day Harrison Crowe took out the men's event before earning a ticket to the Masters and British Open.
Even bigger spoils could be within the pair's grasp on Sunday.
"I know them quite well," Guan said of Bosio and Hammett.
"They're really great players and it's no surprise to see them up there."
