Southern California’s rising stars, longtime friends and training partners since 2021, 19-year-old Learner Tien from Irvine and 20-year-old Alex Michelsen of Aliso Viejo, have made history at the 2025 Australian Open, becoming the first pair of American men age 20 or younger to reach the third round at a Grand Slam event since the 2003 US Open (Andy Roddick, 20; Robby Ginepri, 20) and at the Australian Open since 1990 (Pete Sampras, 18; David Wheaton, 20). 

Tien’s journey to this milestone has been nothing short of remarkable. After reaching a career-high of No. 4 in the ITF junior rankings in 2023, Tien’s junior career included finishing runner-up in the Junior Boys’ singles events at both the Australian and US Opens and capturing the Junior Boys’ doubles crown in Melbourne with Cooper Williams. His impressive junior career showcased his potential early, establishing him as one of the top young players to watch.

Reflecting on his progress, Tien shared, “I know it’s kind of a cliché, but you dream of moments like this when you’re a little kid. I know it’s just the second round, but it’s something I’m really proud of.”

The first Australian Open qualifier to defeat an ATP top-5 opponent since 2005, Tien’s breakthrough comes after a series of significant achievements.

Just two summers ago, Tien had won his second consecutive USTA Boys’ 18s National Championship in Kalamazoo, Michigan, which earned him a wild card into the main draw of the US Open. He faced world No. 32 Miomir Kecmanovic in the opening round at Flushing Meadows, falling in straight sets, but the experience only fueled his fire. Tien also made history at the 2023 US Open by winning his first Grand Slam match in the doubles draw.

Tien announced in November of 2023 his decision to turn pro after previously committing to the University of Southern California. He made his ATP Tour main-draw debut at the 2023 BNP Paribas Open as a wild card and earned his first professional victory in September at an ATP Challenger event in Cary, North Carolina. A semifinal appearance at a Challenger event in Fairfield, California, and another final-round showing at a Futures event in Naples, Florida, rounded out his 2023 season.

The 2024 season marked the meteoric rise of Tien, a then-18-year-old tennis sensation whose journey embodies resilience, skill, and an unwavering hunger for greatness. What began as a challenging year, marred by injury, evolved into a breathtaking narrative of triumph and determination, culminating in one of the most remarkable upsets in recent tennis history.

Learner Tien’s ascent to tennis prominence wasn’t without hurdles. Starting the year ranked outside the world’s Top 450, his future seemed uncertain after fracturing a rib during the M25 Naples tournament in February. Forced off the court for months, Tien’s return at the M15 San Diego event, part of the SoCal Pro Series, in late May was nothing short of spectacular. He launched a 28-match winning streak, clinching four SoCal Pro Series titles in San Diego, Rancho Santa Fe, and Lakewood, as well as his maiden ATP Challenger title in Bloomfield Hills, Michigan. The lefty became the 10th youngest American Challenger champion since 1990.

By November, Tien had climbed to a career-high ATP ranking of No. 114, earning his spot among the elite at the Next Gen ATP Finals in Jeddah. His achievements on the USTA Pro Circuit, including seven professional titles and 60 match wins across ITF and ATP Challenger events, showcased his undeniable potential. But it is his 2025 Australian Open run that has truly cemented his place in tennis history.

Facing Daniil Medvedev, a three-time Australian Open finalist and former U.S. Open champion, in the second round was a daunting challenge for Tien. Yet, the young Southern Californian proved more than ready. In a five-set thriller that spanned four hours and 49 minutes and ended just before 3 a.m., Tien stunned the No. 5 seed with a 6-3, 7-6(4), 6-7(8), 1-6, 7-6(10-7) victory.

Medvedev, known for his tactical prowess and relentless court coverage, was pushed to his limits by Tien’s fearless play and intelligent shot-making. Tien displayed remarkable composure, matching Medvedev’s stamina and breaking down his defenses with precision. Despite losing a tightly contested third set and being overpowered in the fourth, Tien roared back in the fifth, ultimately clinching the win with a decisive service winner.

“I made it a lot harder than it could’ve been, but whatever,” Tien said on court right afterward reflecting his grounded demeanor even after the biggest win of his career. He then told the crowd: “I really appreciate all you guys staying out here. I know it’s late. I have no idea what time it is.”

Because of the time difference, the match ended at about 8 a.m. on Thursday morning back home in California, and Tien took the microphone to speak directly to his family — he said he hoped they were tuned in on TV.

“I don’t know if my parents are still watching… I love you guys. Thank you for always supporting me from across the world,” Tien said. “I know you guys wish you could be here. I wish you could be here, too.”

Tien, who is ranked 121 and owned a career Grand Slam record of 0-3 before this week, definitely made a statement on Margaret Court Arena. Despite only recently picking up his first career Grand Slam singles main draw victory, his unwavering belief in his abilities and his consistent approach were pivotal to his success.

“Belief is a big thing in succeeding and winning, in general. I always go on the court believing that there’s a chance I can win,” said Tien, who showed up at his news conference toting a white cardboard box with a pepperoni pizza. “I wasn’t trying to think of the match as anything more important than any other match I’ve ever played. I was just going to go out there, have fun, see what I could do.”

The victory over Medvedev wasn’t just an upset; it was a statement. Tien became the youngest American to reach the Australian Open third round since Donald Young in 2007 and the second-youngest ever after fellow Southern Californian Pete Sampras in 1990. His tactical brilliance, deceptive power, and unrelenting determination were on full display, earning him accolades from fans and peers alike.

“Man, Learner’s just super tough,” said compatriot Govind Nanda of Loma Linda. “He moves you around a lot and plays [at a] very high percentage, then pulls the trigger when he wants to without much risk.”

As Medvedev grasped at uncharacteristic tactics—including serve-and-volley plays—to regain control, Tien remained steadfast. Even in the face of Medvedev’s signature “Octopus” defense, Tien’s ability to inject pace and change direction down the line repeatedly broke his opponent’s rhythm. His relentless hustle and mental fortitude proved too much for the Russian star.

With his Australian Open journey still unfolding, Tien now faces France’s Corentin Moutet in the third round. As he continues to ride the wave of momentum, his performance serves as a reminder of the exciting new generation of tennis stars emerging on the global stage.

From his humble beginnings as the son of Vietnamese immigrants in Irvine, California, to his historic upset in Melbourne, Learner Tien’s story is a testament to hard work and resilience. His name—inspired by his mother’s career as a teacher—now carries a new meaning: a symbol of his own “learning” and rapid mastery of the sport.

At just 19 years old, Tien has already achieved more than most could dream of. But if his 2024 season and Medvedev upset are any indication, this is only the beginning for one of tennis’ brightest young talents.

While Tien has been capturing headlines, Alex Michelsen has also been making waves. Earlier in the tournament, unseeded Michelsen achieved the biggest win of his career by defeating No. 11 Stefanos Tsitsipas in the first round of the Australian Open. His victory propelled him into the third round, making him one of six American men to achieve this feat. Known for his composure and aggressive playing style, Michelsen demonstrated his ability to thrive under pressure, firing 46 winners and showcasing his versatility against top-tier opponents. Reflecting on his performance, Michelsen said, “I went in with a specific game plan for Stef, and it worked perfectly. Playing that aggressively, I feel like I could use this approach against a lot of guys.”

Michelsen, who broke into the Top 50 in August, is the youngest American man to achieve that ranking since Sam Querrey in 2007. Later this month, he is set to make his Davis Cup debut against Chinese Taipei.

Michelsen’s rise has been nothing short of remarkable. Hailing from Southern California, he honed his skills through USTA junior events, amassing an impressive 451-207 record in junior competition. He competed in prestigious tournaments like the National Clay Court Championships and the Southern California Sectionals. In 2021, his standout performances at the USTA Boys’ 18 & 16 National Championships solidified his status as one of Southern California’s top prospects.

Transitioning to the professional circuit, Michelsen has successfully translated his junior achievements into results on the big stage. At the Australian Open, his composure and aggressive playing style have set him apart. His first-round upset of Tsitsipas showcased his ability to thrive under pressure. Michelsen’s aggressive tactics kept his opponent on the backfoot, while his defense—including several on-the-run backhand winners—highlighted his versatility.

“Probably the only other time I’ve played that well was against [Alex] de Minaur in Cabo last year,” Michelsen said in a post-match interview with ATPTour.com. “I went in with a specific game plan for Stef, and it worked perfectly. Playing that aggressively, I feel like I could use this approach against a lot of guys.”

Michelsen fired 46 winners en route to his first Top 20 win at a Grand Slam. In his second-round match, he defeated Australia’s James McCabe in straight sets, 7-5, 6-3, 7-6(4) to match his previous best Grand Slam result of reaching the third round in Melbourne.

The Southern California success story extends beyond Tien and Michelsen. Taylor Fritz, a Rancho Santa Fe native, continues to soar in professional tennis. In 2022, he broke into the Top 10 for the first time, ending the year ranked No. 9. That same year, he defeated Rafael Nadal to secure his first ATP 1000 title at the BNP Paribas Open, becoming the youngest American to win at Indian Wells since Orange County’s Michael Chang in 1996. Fritz made waves again in 2024 by reaching the US Open final, the first American man to do so in 15 years.

This year, Fritz is off to a stellar start at the Australian Open, where he has yet to drop a set. He opened with a commanding 6-2, 6-0, 6-3 victory over Jenson Brooksby, followed by a dominant 6-2, 6-1, 6-0 win against Cristian Garín. In a heartfelt gesture, Fritz announced he would donate his $82,000 prize money from the first round to wildfire relief efforts in Los Angeles.

“Southern California is my home, and I just want to help however I can,” Fritz shared.

Up next, Fritz faces veteran Gael Monfils, who recently made history as the oldest man to win an ATP title at 8. Their matchup promises to be an exciting showdown.

Meanwhile, Thousand Oaks native Marcos Giron is making headlines with a stellar run at the Australian Open, reaching the third round for the first time in his six appearances. A former top junior and standout at UCLA, Giron has overcome significant challenges, including hip surgeries in 2015 and 2016, to play the best tennis of his career eight years later.

Giron’s journey in Melbourne has been as grueling as it is inspiring. In the first round, he rallied from a set down to defeat USC alum Yannick Hanfmann 2-6, 7-5, 6-1, 7-5. He followed that up with a marathon five-set win against Tomas Etcheverry, firing eight aces to claim a hard-fought 7-5, 3-6, 7-5, 3-6, 6-4 victory.

With perseverance and grit defining his campaign, Giron is proving to be a player to watch as the tournament heats up.

Together, Tien, Michelsen, Fritz, and Giron represent the incredible depth of tennis talent emerging from Southern California. Their stories, marked by hard work and determination, continue to inspire fans and highlight the region’s rich tennis legacy.