Little-known Australian Li Tu was the talk of the tennis world for a couple of fun hours on Wednesday morning (AEST).

The 28-year-old from Adelaide had the late night Arthur Ashe Stadium crowd eating out of the palm of his hand as he apologised for a terrible underarm serve and then stunned Carlos Alcaraz by winning the second set and cupping his hand to his ear.

Google was getting a hammering as fans tried to work out just who this talented upstart in the first round of the US Open was.

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Tu, ranked 186th in the world, had scraped into the main draw by saving two match points and then beating Jesper de Jong 3-6, 6-1, 7-5 in qualifying.

He then found out that he was playing the mighty Alcaraz thanks to an Instagram DM from a fan.

“I just read it and I was like no way!”

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Third seed Alcaraz’s pedigree prevailed as the Spanish superstar rallied for a 6-2, 4-6, 6-3, 6-1 win.

But Tu’s role in the match was as heartwarming as it was entertaining as he lapped up every minute of his overdue arrival on the big stage.

Tu was once a teenage prodigy who battled with Thanasi Kokkinakis for the mantle of Australia’s No.1 junior in his age group.

But the pressure all got a bit much and Tu quit the sport at 18.

“I live with no regrets, and I think at the time, everything works out as it should be,” Tu told ATPTour.com before the Alcaraz match.

“I look back, and I think that it was all a bit too much for me, the expectations. I really was a bit burnt out.”

Tu then earned a Bachelor of Commerce from Adelaide University in 2017 before starting a tennis coaching business.

He returned to the court competitively after a six year break in 2021 and has since chalked up nine ITF titles.

Tu’s inspiration is his late mother, Yu Ping Zheng, who died two years ago from lung cancer.

“We all still miss her every day,” Tu told ATPTour.com.

“Every time we talk about her, we sort of tear up a little bit, and she really was one of the best people. We miss her. We miss her dearly…

“I got a wild card into the 2021 (Australian Open), but how that all happened, it was pretty weird. This one, I earned it. I did it, I qualified. Playing a major is stuff that people dream about, that I dreamed as a kid as well. And to really do it, do it properly, it’s just truly amazing.”

Alcaraz showered praise on Tu in his on court interview with Nick Kyrgios.

“I actually grew up with him since we were 10-years-old and it was incredible to see how far he’s come,” Kyrgios informed Alcaraz.

“He quit the sport for six years, came back and now he’s on court with one of the best players that’s ever going to play this game.”

Alcaraz admitted he was surprised by Tu’s level in the first set as it became obvious he could play.

“I was surprised but I’m going to follow him, his results from now, because I am pretty sure that if he’s playing at this level, I’m going to see him around very, very soon.”