Know all details about Learner Tien’s coach Eric Diaz, who is guiding the youngster towards a memorable Australian Open 2025 journey
In a stunning turn of events at the Australian Open, 19-year-old American qualifier Learner Tien pulled off one of the tournament’s biggest upsets, defeating fifth seed Daniil Medvedev in a thrilling five-set showdown. After nearly five hours of grueling play, the Tien emerged victorious, securing a hard-fought win with a final score of 6-3, 7-6 (7-4), 6-7 (8-10), 1-6, 7-6 (10-7).
Who is Eric Diaz, tennis coach of Learner Tien, bio, age, family, dad, brothers, education, nationality and stats
Learner Tien, a rising tennis star, has captured the attention of fans and experts alike with his impressive achievements at just 19 years old. Recently, he broke into the Top 200, clinched three ATP Challenger Tour titles, and made it to the second round of the Melbourne Major after successfully clearing the AO qualifiers. However, Tien’s success isn’t solely due to his talent—it’s the result of the guidance he’s received from his coaches, particularly Eric Diaz.
If Learner Tien (or his coach Eric Diaz) wrote a book about how Tien upset of Daniil Medvedev happened "The Education of a Tennis Player" would also be a great title! https://t.co/oBqyjW42aN
— Randy Walker (@TennisPublisher) January 16, 2025
Who is Eric Diaz?
Tien’s tennis journey began early, growing up in a household where both parents who are immigrants from Vietnam played the sport recreationally. His father, Khuong, a real estate lawyer initially coached him until Tien joined the USTA player development program around the age of 10-11. It was during his teenage years that he met Eric Diaz, who would become his first official coach and has continued to support him throughout his career.
Eric Diaz, himself hailing from a tennis family, has a deep understanding of developing young talent. His father, Manny Diaz, is a well-known figure in the tennis world, having coached the University of Georgia men’s team. Manny is married to the former Suzanne Rondeau of Toronto, Canada and they have three sons, Alex, Eric and Manuel III.
Manuel Diaz, the SEC’s all-time winningest coach who ranks sixth in NCAA men’s tennis history with 781 career victories and served as Georgia’s head coach for 36 years.
When Eric Diaz first encountered Tien, he immediately recognized the potential in the young player, describing him as having a unique “aura” despite his quiet demeanor.
This calm confidence has been evident on the court, with Tien winning the USTA Boys’ 18s National Hard Court Championships twice and reaching his first ATP Tour quarterfinal at the Winston-Salem Open, making him the youngest American man in the Top 200 since Stefan Kozlov in 2016. Tien’s junior career has been equally remarkable, with a peak ranking of No. 4 and notable achievements, including reaching the finals of both the Australian Open and US Open in 2023, as well as winning the boys’ doubles title at the Australian Open alongside Cooper Williams.
After a successful college career that included 95 doubles wins being a part of two Final Four teams, Diaz caught the coaching bug with open arms.
He joined the Boise State staff fresh out of college and pivoted to the club level, settling in at the Coto Tennis Club in the Orange County region of Southern California. Eric works for a group called “Tier 1 Performance,” a full-time tennis training program that stresses individualized instruction from teaching pros to students.
Diaz’s coaching experience includes helping at Bulldog tennis camps, working as an assistant coach at the Beck Tennis Academy in Athens, Ga., and attending a USTA high performance coaching program led by Jose Higueras and he received a three month internship to work with the USTA player development program. Diaz worked with elite American athletes ranging in age from 12-18, as well as ATP and Challenge players throughout his internship period.
Diaz has also worked with a Collegiate Tour Team where he assisted Stephen Armitraj and Brad Stine for several weeks, which included time at the U.S. Open and a a collegiate player he experienced success as a member of four SEC regular-season championship teams, two SEC Tournament Champions, two NCAA Final Four teams and three top-five nationally ranked squads.
In addition to serving as team co-captain during his senior season, Diaz was ranked nationally with two different doubles partners and graduated from the University of Georgia in the spring of 2015 with a degree in communication studies.
He has remained active playing tennis since his graduation and is a member of the Puerto Rico Davis Cup team. He is aged 33 and is a left handed tennis player.
Despite his success, Tien’s journey has had its challenges. A setback in June 2024, when he fractured his seventh rib, kept him off the court for over three months. Diaz took a careful approach to Tien’s return, focusing on improving his forehand and serve. This strategy proved effective, as Tien returned stronger, winning his first 28 matches and qualifying for the Next Gen ATP Finals.
UNBELIEVABLE!
19 year old Learner Tien gets an INCREDIBLE win over world #5 and three time runner up Daniil Medvedev 6-3, 7-6(4), 6-7(8), 1-6, 7-6(10-7) to reach the 3rd round at the #AusOpen.
4h48
2.55am
Had a MP in the 3rd set tiebreak, won the match TWO hours later.
WOW pic.twitter.com/4JxDROU46U
— José Morgado (@josemorgado) January 16, 2025