Jan Kumstát (born 2 January 2007) is a Czech tennis player. He has a career-high ATP singles ranking of No. 184 achieved on 14 September 2026 and a doubles ranking of No. 449 achieved on 28 September 2026.
Kumstát won the boys' doubles title at the 2025 Australian Open.
Junior career In the summer of 2022, Kumstát won gold in the singles at the European Youth Olympic Festival in Banská Bystrica.
He was part of the Czech team that won the 2023 Junior Davis Cup.
He made his Junior Grand Slam debut at the 2024 Australian Open. He defeated local opponent Hayden Jones on his way to reaching the final, where he lost to Japanese Rei Sakamoto. He also reached the quarterfinals in the doubles category, with Norwegian Nicolai Budkov Kjær.
Playing with compatriot Jan Klimas, Kumstát was a runner-up in the boys' doubles event at the 2024 Wimbledon Championships. The pair was defeated by Alexander Razeghi and Max Schönhaus in the final.
Kumstát went into the 2025 Australian Open as the highest-ranked junior in the tournament. He reached the quarterfinals in boys' singles, but lost to Swiss Henry Bernet. Despite that loss, a few days later he reached the doubles final in Melbourne, with American Maxwell Exsted. They were crowned champions of that event, defeating Ognjen Milić and Egor Pleshivtsev in straight sets.
Kumstát also had good results on the ITF junior circuit, maintaining a 76–40 singles win-loss record and reached an ITF junior combined ranking of world No. 3 on 6 January 2025.
Professional career 2025: Pro beginnings Playing on Pro Tour Kumstát reached his first two ITF singles finals at back to back events in Italy and Slovenia. In doubles he played another two finals with fellow Czech players David Poljak and Denis Peták.
He also made his ATP Challenger Tour debut in Ostrava defeating Murphy Cassone in the first round.
2026: Three successive Challenger titles, top 200 In August, he won his second ATP Challenger title at the 2026 Hamburg Ladies & Gents Cup, following his triumph on home soil in Liberec, earlier in the month. As a result, he reached the top 250, raising 100 positions in the ATP singles rankings on 24 August 2026. He won his third Challenger title in a row as a teenager, the third to accomplish the feat after Guillermo Coria and Grigor Dimitrov, at home at the 2026 Sekyra Group Prague Open by Advantage Cars and reached the top 200 on 24 August 2026.
Personal life Kumstát is from Prostějov, Czechia. He is the son of former ice hockey player Pavel Kumstát and nephew of Petr Kumstát. His mother, Kateřina, was a professional volleyball player.
ATP Challenger Tour finals
Singles: 3 (3 titles) LegendATP Challenger (3–0)Finals by surfaceClay (3–0)
ResultW–LDateTournamentTierSurfaceOpponentScoreWin1–0Svijany Open, Czech RepublicChallengerClay Gonzalo Bueno6–3, 6–1Win2–0Hamburg Ladies & Gents Cup, GermanyChallengerClay Marvin Möller4–6, 7–6(7–5), 7–5Win3–0Prague Open, Czech RepublicChallengerClay Tseng Chun-hsin5–7, 6–3, 6–0
ITF World Tennis Tour finals
Singles: 3 (3 runner-ups) LegendITF WTT (0–3)Finals by surfaceHard (0–1)Clay (0–2)
ResultW–LDateTournamentTierSurfaceOpponentScoreLoss0–1M15 Segrate, ItalyWTTClay Alexander Weis4–6, 7–6(8–6), 1–6Loss0–2M15 Slovenska Bistrica, SloveniaWTTClay Juan Cruz Martin Manzano4–6, 7–6(7–3), 1–4, ret.Loss0–3M15 Heraklion, GreeceWTTHard Henry Searle2–6, 2–6
Doubles: 4 (2 titles, 2 runner-ups) LegendITF WTT (2–2)Finals by surfaceHard (2–0)Clay (0–2)
ResultW–LDateTournamentTierSurfacePartnerOpponentsScoreLoss0–1M15 Szentendre, HungaryWTTClay Denis Peták Alberto Barroso Campos Johan Nikles6–7(6–8), 6–7(5–7)Loss0–2M25 Česká Lípa, Czech RepublicWTTClay David Poljak Vladyslav Orlov Filippo Romano6–7(4–7), 1–6Win1–2M15 Monastir, TunisiaWTTHard Piotr Pawlak Adan Freire da Silva Yanis Ghazouani Durand7–5, 6–3Win2–2M15 Monastir, TunisiaWTTHard Jakub Nicod Pieter De Lange Daniil Sarksian6–3, 6–7(5–7), [11–9]
Junior Grand Slam finals
Singles: 1 (runner-up) ResultYearTournamentSurfaceOpponentScoreLoss2024Australian OpenHard Rei Sakamoto6–3, 6–7(3–7), 5–7
Doubles: 2 (1 title, 1 runner-up) ResultYearTournamentSurfacePartnerOpponentsScoreLoss2024WimbledonGrass Jan Klimas Alexander Razeghi Max Schönhaus6–7(1–7), 4–6Win2025Australian OpenHard Maxwell Exsted Ognjen Milić Egor Pleshivtsev7–6(8–6), 6–3
References
External links