Jason Murray Kubler (/ˈkuːblər/ KOOB-lər;[3] born 19 May 1993) is an Australian professional tennis player. He has a career-high ATP singles ranking of No. 63 achieved on 24 April 2023 and a doubles ranking of No. 27 achieved on 22 May 2023. Kubler's career highlight came at the 2023 Australian Open, where he won his first Grand Slam doubles title as a wildcard alongside compatriot Rinky Hijikata.[4]
Despite a promising junior career, which included the junior world No. 1 ranking and comparisons to Rafael Nadal,[5][6][7][8] Kubler has spent the majority of his professional career on the lower circuits due to a hereditary knee condition that results in weakened meniscus around the joints.[9] The condition has plagued Kubler throughout his career, resulting in six knee surgeries.[10] Kubler also spent four years of his professional career playing exclusively on clay courts to avoid further structural damage to his knees.[9]
Kubler was born in Brisbane, Australia to an Australian father and a Filipina mother.[11] His father, John, introduced Kubler to tennis at the age of five,[8] but died of cancer when Kubler was eight years of age.[5] Kubler grew up in the north Brisbane suburb of Mango Hill[12] with an older brother and a younger sister.[13]
In 2009, Kubler became just the second player in history (after Rafael Nadal) to go undefeated through the World Youth Cup and Junior Davis Cup.[5] Following his success at the Junior Davis Cup, Kubler won five titles in a row which saw his junior ranking rise to No. 3 in the world.
Kubler won six junior titles throughout his career and achieved the combined No.1 world ranking in May 2010 with a win–loss record of 67–17 in singles and 40–19 in doubles.
Kubler made his professional debut in September 2008 at the Australia F7 Futures event on the ITF Men's Circuit, the third tier for men's professional tennis. Kubler won through qualifying to make his main draw professional debut but lost in the first round to compatriot Marinko Matosevic.[14]
In 2010, following continued success on the junior circuit, Kubler was granted wildcards into the Brisbane International and Sydney International qualifying draws, but failed to win a match at either event. He was then awarded a wildcard to make his ATP Tour and Grand Slam debut at the 2010 Australian Open. Drawn against 24th seed Ivan Ljubičić, Kubler was handily beaten 6–2 6–1 6–1 in a lacklustre display.
In April, Kubler won the first main draw professional match of his career at the Australia F3 Futures event in Ipswich, where he went on to make the final, losing to Brydan Klein.[15] Kubler's best results for the remainder of 2010 were a string of semi-final appearances at Netherlands F2, Italy F23, Portugal F5 and Spain F37 Futures events. He finished the season ranked No. 535 in the world.
Kubler missed the start of the 2011 Australian summer of tennis due to a knee injury.[16] Further injuries during the year limited his play before he won the first professional title of his career at the USA F28 Futures event in Birmingham, defeating Yoshihito Nishioka in the final.[17] Kubler won his second professional title the next week at the USA F29 Futures event in Niceville, salvaging an otherwise frustrating year with injury. He finished the 2011 season ranked No. 530 in the world.
Kubler began the 2012 season by entering four Futures tournaments in Florida after again bypassing the Australian summer. Kubler lost in the final of USA F1 to Jack Sock and USA F3 to Brian Baker before winning the USA F4 event in Palm Coast to cap off a promising start to the year. Kubler returned to Australia in March, where he lost the final of the Australia F3 event against Sam Groth but defeated John Millman to claim the Australia F4 title in Bundaberg. Kubler then travelled to Europe, to compete in further Futures tournaments and the first Challenger events of his career, where he made a quarter-final at the Todi Challenger in September. Following more success on the Futures tour, Kubler's world ranking steadily rose, peaking at a career-high No. 268 on 29 October 2012. He ended the 2012 season ranked No. 332 in the world.
In 2013, Kubler played in Futures tournaments throughout the United States, Spain, Great Britain, Australia, Italy and Egypt, but only on clay due to ongoing knee concerns. He won three Futures tournaments for the year, however his ranking dipped to No. 397 to end the season.
Kubler again chose to miss the Australian summer of tennis, opting to play Futures events in Egypt and Spain. He entered six tournaments during this stretch, making the final of three and winning one. In March, Kubler qualified for the main draw of Challenger events in Panama and Barranquilla, but failed to win a match at either tournament. In April, he competed in further Challenger events in Savannah and Tallahassee, making the second round at both tournaments. In May, Kubler qualified for the ATP event in Düsseldorf, his first ATP World Tour event since the 2010 Australian Open. He won his first tour-level match by defeating Alessandro Giannessi, before losing to Denis Istomin in the second round.[18] In June, Kubler returned to the Futures circuit and defeated the number one seed Kimmer Coppejans in the final of the Netherlands F3 in Breda. He broke into the top 200 for the first time on 25 August 2014 at No. 197. In September, Kubler made the quarter-final of the Biella Challenger and the following week, he won the Sibiu Challenger defeating Radu Albot in the final[19] This was the first Challenger title of his career.[20] In November, Kubler reached the final of the Lima Challenger, losing to Guido Pella. On 24 November, Kubler reached a career high ranking of No. 136 before finishing the 2014 season with a world ranking of No. 140. Kubler played a total of 29 tournaments in 14 countries in 2014, all of which were on clay, due to his ongoing knee problems.[21]
Kubler skipped the Australian summer of tennis for a fifth consecutive year. He instead played a variety of Challenger events across South and North America, his best result being a quarter-final appearance in Sarasota. In May, Kubler attempted to qualify for the French Open, but lost in the first round to Tim Pütz. This was Kubler's first appearance at a Grand Slam event in five years, albeit in the qualifying tournament. In June, Kubler entered the qualifying tournament at Wimbledon, marking his first competitive appearance on the grass in three years.[22] He defeated Rui Machado in straight sets in round 1 but was eliminated in the second round by Aleksandr Nedovyesov, who went on to qualify for the main draw. In September, Kubler attempted to qualify for the US Open, but lost in the opening round to Facundo Bagnis. This was Kubler's first competitive hard court appearance at any professional level in five years. Following the US Open, Kubler underwent knee surgery.[10] A lacklustre year on the court and limited tournament play saw Kubler's ranking freefall to No. 544 to end the 2015 season.
After rehabbing from knee surgery, Kubler commenced the 2016 season by playing several Futures events in North America. He reached the quarter-final of USA F6 and semi-final of USA F8 in February. At USA F9 in March, Kubler retired in the first round. In May, just eight months after his last surgery, Kubler underwent the sixth knee operation of his career which side lined him for the rest of 2016.[23] As a result, Kubler finished the year ranked outside the world's top 1000.
After a year out of the game and without a world ranking, Kubler returned to professional tennis in March at the Australia F2 and F3 Futures events in Canberra. In the lead up to the events, Kubler was frank about his future in the sport, commenting that another knee operation would likely mark the end of his career.[24] After little success in Canberra, Kubler travelled to Europe in April for Futures events in Spain and Italy. Although Kubler managed to make a semi-final appearance at Spain F12, the highlight of his European trip was a doubles title with compatriot Alex Bolt at the Italy F14 tournament. This was Kubler's first professional trophy of any kind since 2014.
In October, Kubler won through qualifying at the Traralgon ATP Challenger and made a remarkable run to the final after defeating two former top 100 players in Taro Daniel and Matthew Ebden. He defeated Alex Bolt in the final to claim his first Challenger title since 2014, which skyrocketed his ranking inside the world's top 350. Kubler was expected to compete in the Australian Wildcard Playoff in December for a spot in the 2018 Australian Open, but ultimately withdrew alongside a host of top-seeded players.[25] Kubler finished the year ranked No. 341 in the world.
Kubler started his 2018 campaign at the Playford Challenger in South Australia, which he won after qualifying. The victory saw Kubler move inside the world's top 250 for the first time since 2015. Following an impressive run of form and a huge improvement in ranking over the past six months, Kubler was awarded the final wildcard into the 2018 Australian Open, his first Grand Slam appearance in eight years.[26] Kubler faced 10th seed Pablo Carreño Busta in the first round, where he lost in a highly competitive four-set match. Kubler showed plenty of promise in the match, leading by a break in both the first and third sets, but failed to capitalise on his opportunities. Following the Australian Open, Kubler competed in nine Challenger events across Australia and Asia from February to May. His best results through this stretch included three semi-final appearances at the Burnie International, Quijing International and Seoul Open. Kubler improved his world ranking to No. 160 following the Asian swing, his best world ranking in three years.
At the French Open, Kubler lost in the first round of qualifying to Gonçalo Oliveira. Following the French Open, Kubler proceeded to lose in the first round at his next three Challenger tournaments before making a semi-final run at the Ilkey Trophy, where he eventually lost to Oscar Otte. The result saw Kubler return to the world's top 150 for the first time in more than three years.
Kubler then entered the Wimbledon qualifying tournament and showed good form through his first two matches, defeating Arthur De Greef and Adam Pavlásek. In the final round of qualifying, Kubler defeated Canadian journeyman Peter Polansky in four-sets to qualify for the Wimbledon main-draw for the first time in his career. Heading into Wimbledon, Kubler's remarkable comeback journey started to gain attention and his story was captured by the ATP in a video feature titled "The Comeback Story of Jason Kubler".[27] Kubler faced unseeded Argentinian Guido Pella in the first round, where he lost in four close sets. Following Wimbledon, Kubler entered the Winnipeg Challenger. As the fourth seed, Kubler dropped just one-set the whole tournament to claim his second Challenger title of the year, defeating Lucas Miedler in the final. The result saw Kubler move to No. 114 in the ATP rankings, eclipsing the career high he set way back in November 2014. To finish his Canadian tour, Kubler made the semi-final of the Gatineau Challenger before withdrawing from the Granby Challenger with knee soreness.
Kubler then attempted to qualify for the Washington Open, an ATP 500 event. Despite losing in the final round of qualifying, Kubler was granted entry into the main draw as a lucky loser after Nick Kyrgios withdrew with a hip injury. Taking Kyrgios' seeding, Kubler progressed through to the second round via a bye before losing in a third set tie-breaker to fellow Australian James Duckworth. In August, Kubler was granted a reciprocal wildcard into the US Open.[28] In the lead up to the tournament, Kubler competed in the Vancouver Open on the Challenger circuit, where he was defeated by Dan Evans in the final. The result propelled Kubler into the top 100 for the first time, marking an 841 place ranking rise in the past 12 months.[29] At the US Open, Kubler upset 19th seed Roberto Bautista Agut in straight sets in the first round to claim the first main draw grand slam win of his career.[30] In the second round, Kubler was forced to retire in the fourth-set against American Taylor Fritz after rolling his ankle, which inadvertently caused further problems with his knees.[31][32]
Kubler finished the season ranked No. 114 in the world.
Kubler was expected to compete in the Brisbane International, but withdrew from the event due to knee soreness.[33] Kubler then attempted to qualify for the Sydney International, but fell in the first round to third seed Yoshihito Nishioka. For the second consecutive year, Kubler was awarded a wildcard into the 2019 Australian Open.[34] With limited tournament preparation, Kubler was defeated in the first round of the Australian Open by unseeded Italian Thomas Fabbiano in four sets.
Following a three-month break from the tour due to knee ailments,[35] Kubler returned in mid-April at the Kunming Challenger where he was defeated by James Duckworth in the third round. At the 2019 French Open, Kubler attempted to qualify but was defeated in the second round by Viktor Troicki. At Wimbledon, Kubler won through his first two matches in qualifying but fell at the last hurdle to Yasutaka Uchiyama in five sets. Following his poor results, Kubler's ranking dipped to No. 211 in the world. In July, Kubler made back-to-back finals on the Challenger tour in Winnetka and Gatineau. Kubler lost the Winnetka final to top-seeded American Bradley Klahn but bounced back to win the Gatineau tournament without dropping a set. The result helped steer Kubler back inside the top 200 at No. 189 in the ATP rankings. Kubler was expected to contest the Challenger event in Granby, but withdrew due to a wris