It is only three years since Lerner Tien was contesting a Australian Open boys final.In 2023, a 17-year-old Tien was losing in three sets to Belgium’s Alexander Blockx in Melbourne, but it is a very different story just a few years on.Tien is bidding to become the first American man since Andy Roddick in 2003 to win a Grand Slam singles titleGettyTien only turned 20 in December but is already making waves at the US Open and creating history in the process.He defeated Jakub Mensik, 6-3, 1-6, 6-7(2), 6-3, 6-4, in the third round to continue his career-best run at his home Grand Slam.In doing so, Tien became the youngest American man to make it to the US Open fourth round since Andy Roddick in 2002, a year before Roddick won his US Open title.The young American tennis star, ranked 15th on the ATP Tour, faces Karen Khachanov in the next round.He could crack the world’s top-10 if he makes the semi-finals in New York, where he could face Alexander Zverev.There are currently five American men in the Round of 16 including Tommy Paul, Frances Tiafoe, Ben Shelton, Alex Michelsen, and Tien.All are bidding to become the first American man to win a Grand Slam since Roddick’s US Open victory in 2003.Learner Tien’s roots and name originHailing from Irvine, California, Tien’s back story and his name have gathered plenty of headlines.He is named after his mother, who is a teacher, while his sister – Justice and is named after the chosen occupation of their father, a lawyer.Although he hasn’t always enjoyed the questions that come with a slightly different name.The 20-year-old won the NextGen Finals in Saudi Arabia last yearGettyTien has dazzled in Melbourne to reach his first ever Grand Slam quarterfinalAFP“I like it a little more now just because it’s so unique,” he told the Los Angeles Times.“I haven’t met anyone with the same name as me. Or heard of anyone with the same name as me. I like it in that sense. Besides that, it’s just a name.”Tien honed his passion on community courts in Irvine under his father, and his early passion for the sport quickly turned into a quality.“I started when I was little older than one,” Tien told the Guardian earlier this year.“I think (it was) one of my dad’s old rackets that were lying around. “So they didn’t really even expect for me or my sister to start playing tennis that young. “It’s not like they were prepped with little kiddy rackets or anything.“My parents would play recreationally. I got to the courts a couple times a week, just with my dad, just watching him play in random men’s leagues.“So that’s kind of how I got introduced. Eventually my dad started taking me to the courts, randomly feeding me balls from a pretty young age, and then it kind of just progressed from there on.”After turning pro in the summer of the 2023, Tien won his first title in 2025GETTYTien was beaten by Novak Djokovic in New York last yearGETTYTien went on to excel in junior tournaments and secured a spot in the prestigious United States Tennis Association youth development programme.Although tennis for a while wasn’t Tien’s priority, he had entered high school early at the age of 11 after being homeschooled by his mom.“The tennis wasn’t really in the picture yet,” Tien says.“My sister is a few years older than me, so my mom retired when my sister was born, so she was already just at home with my sister starting to teach my sister. So she just thought she’d teach me, too.“I started school young. I would work through the year. I wouldn’t have summer break and stuff like that. I would just work throughout the year. So I just naturally finished those early grades pretty quick. And then, yeah, I didn’t see really a reason just to stop me there. So I just went into high school.“I obviously like tennis more than I like school, so it was a good motivation for me to kind of get away from school just to go and play. But throughout juniors, my parents did a very good job, honestly, of not putting a lot of pressure on me to win”It’s safe to say tennis is definitely Tien’s priority now.Tien is one of five American men remaining at the 2026 US OpenGettyHe faces Karen Khachanov in the next roundGettyA 2025 to remember for Learner TienWhile the young American stands on the brink of his own history, it was in 2025 that he made his mark.12 months ago he won his first ever Grand Slam singles match at the Australian Open going on to become the youngest man since Rafael Nadal in 2005 to reach the fourth round.In that same tournament, he announced himself to the world when he claimed his maiden Top 10 win by defeating Medvedev – a feat he has gone on to repeat.He closed out the year with an indifferent run of form, but started the year in perfect fashion, following on from his ATP title breakthrough and NextGen success.Tien continued his red hot form at the 2026 Australian Open, upsetting Medvedev once again in the fourth round in straight sets.With the victory, Tien reached his first Grand Slam tournament quarterfinal, and became the youngest man to reach an Australian Open quarterfinal since 2015.Tien has now racked up more than $5 million in prize money since he turned professional.