Constantin Frantzen
| Country (sports) |  Germany |
|---|---|
| Born | 16 March 1998 Düsseldorf, Germany |
| Height | 1.93 m (6 ft 4 in) |
| Plays | Right-handed (two-handed backhand) |
| College | Baylor University |
| Prize money | US $952,284 |
| Singles | |
| Career record | 0–0 |
| Career titles | 0 |
| Highest ranking | No. 1226 (20 February 2023) |
| Doubles | |
| Career record | 71–73 |
| Career titles | 2 |
| Highest ranking | No. 29 (24 August 2026) |
| Current ranking | No. 36 (26 October 2026) |
| Grand Slam doubles results | |
| Australian Open | 1R (2024, 2025, 2026) |
| French Open | 2R (2025) |
| Wimbledon | QF (2024) |
| US Open | QF (2025) |
| Last updated on: 26 October 2026. | |
Constantin Frantzen (born 16 March 1998) is a German professional tennis player who specializes in doubles. He has a career-high ATP doubles ranking of world No. 29 achieved on 24 August 2026.
Frantzen has won one ATP Tour doubles title at the 2025 Chengdu Open, with Robin Haase.
He played college tennis at Baylor University.
Career
2023–2024: ATP and major debuts in doubles
Frantzen made his ATP Tour doubles main draw debut at the Swiss Open Gstaad alongside Hendrik Jebens.
He reached his first ATP Tour final at the Moselle Open with partner Jebens, but lost to Hugo Nys and Jan Zieliński. Frantzen reached his second ATP Tour final at the 2024 Generali Open Kitzbühel also alongside Jebens but lost to Alexander Erler and Andreas Mies. The pair also made it to the 2024 Hangzhou Open final, losing to Jeevan Nedunchezhiyan and Vijay Sundar Prashanth in the final.
2025: Maiden ATP title
In September, Frantzen won his first doubles title on the ATP Tour at the Chengdu Open, playing alongside Robin Haase.
Doubles performance timeline
| W | F | SF | QF | #R | RR | Q# | DNQ | A | NH |
(W) winner; (F) finalist; (SF) semifinalist; (QF) quarterfinalist; (#R) rounds 4, 3, 2, 1; (RR) round-robin stage; (Q#) qualification round; (DNQ) did not qualify; (A) absent; (NH) not held; (SR) strike rate (events won / competed); (W–L) win–loss record.
To avoid confusion and double counting, these charts are updated at the conclusion of a tournament or when the player's participation has ended.
Current through the 2026 Swiss Indoors.
| Tournament | 2023 | 2024 | 2025 | 2026 | SR | W–L |
|---|---|---|---|---|---|---|
| Grand Slam tournaments | ||||||
| Australian Open | A | 1R | 1R | 1R | 0 / 3 | 0–3 |
| French Open | A | 1R | 2R | 1R | 0 / 3 | 1–3 |
| Wimbledon | A | QF | 3R | 1R | 0 / 3 | 5–3 |
| US Open | A | 1R | QF | 1R | 0 / 3 | 3–3 |
| Win–loss | 0–0 | 3–4 | 6–4 | 0–4 | 0 / 12 | 9–12 |
| ATP 1000 tournaments | ||||||
| Indian Wells Open | A | A | 1R | QF | 0 / 2 | 2–2 |
| Miami Open | A | A | 1R | 1R | 0 / 2 | 0–2 |
| Madrid Open | A | A | 2R | A | 0 / 1 | 1–1 |
| Cincinnati Open | A | A | A | F | 0 / 1 | 4–1 |
| Shanghai Masters | A | A | A | 1R | 0 / 1 | 0–1 |
| Win–loss | 0–0 | 0–0 | 1–3 | 6–4 | 0 / 7 | 7–7 |
| Career statistics | ||||||
| Tournaments | 5 | 20 | 25 | 27 | 77 | |
| Titles | 0 | 0 | 1 | 1 | 2 | |
| Finals | 1 | 2 | 1 | 4 | 8 | |
| Overall win–loss | 3–5 | 19–20 | 23–23 | 28–26 | 73–74 | |
| Year-end ranking | 65 | 52 | 48 | 50% | ||
Significant finals
ATP 1000 tournaments
Doubles: 1 (runner-up)
| Result | Year | Tournament | Surface | Partner | Opponents | Score |
|---|---|---|---|---|---|---|
| Loss | 2026 | Cincinnati Open | Hard |  Robin Haase |
 Orlando Luz Rafael Matos |
4–6, 6–3, [7–10] |
ATP Tour finals
Doubles: 8 (2 titles, 6 runner-ups)
|
|
|
| Result | W–L | Date | Tournament | Tier | Surface | Partner | Opponents | Score |
|---|---|---|---|---|---|---|---|---|
| Loss | 0–1 | Nov 2023 | Moselle Open, France |
ATP 250 | Hard (i) | Hendrik Jebens |
 Hugo Nys Jan Zieliński |
4–6, 4–6 |
| Loss | 0–2 | Jul 2024 | Austrian Open, Austria |
ATP 250 | Clay | Hendrik Jebens |
 Alexander Erler Andreas Mies |
3–6, 6–3, [6–10] |
| Loss | 0–3 | Sep 2024 | Hangzhou Open, China |
ATP 250 | Hard | Hendrik Jebens |
 Jeevan Nedunchezhiyan Vijay Sundar Prashanth |
6–4, 6–7(5–7), [7–10] |
| Win | 1–3 | Sep 2025 | Chengdu Open, China |
ATP 250 | Hard | Robin Haase |
 Vasil Kirkov Bart Stevens |
4–6, 6–3, [10–7] |
| Loss | 1–4 | Feb 2026 | Open Occitanie, France |
ATP 250 | Hard (i) | Robin Haase |
 Théo Arribagé Albano Olivetti |
6–7(6–8), 1–6 |
| Loss | 1–5 | Feb 2026 | Rio Open, Brazil |
ATP 500 | Clay | Robin Haase |
João Fonseca Marcelo Melo |
6–4, 3–6, [8–10] |
| Loss | 1–6 | Aug 2026 | Cincinnati Open, United States |
ATP 1000 | Hard | Robin Haase |
Orlando Luz Rafael Matos |
4–6, 6–3, [7–10] |
| Win | 2–6 | Oct 2026 | European Open, Belgium |
ATP 250 | Hard (i) | Robert Galloway |
Sadio Doumbia Bart Stevens |
6–7(4–7), 6–4, [10–8] |
ATP Challenger finals
Doubles: 18 (9 titles, 9 runner-ups)
| Finals by surface |
|---|
| Hard (2–5) |
| Clay (7–3) |
| Carpet (0–1) |
| Result | W–L | Date | Tournament | Surface | Partner | Opponents | Score |
|---|---|---|---|---|---|---|---|
| Loss | 0–1 | Sep 2022 | Columbus, United States |
Hard |  Charles Broom |
Julian Cash Henry Patten |
2–6, 5–7 |
| Loss | 0–2 | Oct 2022 | Las Vegas, United States |
Hard | Reese Stalder |
Julian Cash Henry Patten |
4–6, 6–7(1–7) |
| Loss | 0–3 | Mar 2023 | Pau, France |
Hard (i) | Julian Cash |
Dan Added Albano Olivetti |
6–3, 1–6, [8–10] |
| Loss | 0–4 | Mar 2023 | Lugano, Switzerland |
Hard (i) | Hendrik Jebens |
 Zizou Bergs David Pel |
2–6, 6–7(6–8) |
| Win | 1–4 | Mar 2023 | Biel/Bienne, Switzerland |
Hard (i) | Hendrik Jebens |
 Victor Vlad Cornea Franko Škugor |
6–2, 6–4 |
| Loss | 1–5 | May 2023 | Mauthausen, Austria |
Clay | Hendrik Jebens |
Romain Arneodo Sam Weissborn |
4–6, 2–6 |
| Win | 2–5 | Jun 2023 | Heilbronn, Germany |
Clay | Hendrik Jebens |
Victor Vlad Cornea Philipp Oswald |
7–6(9–7), 6–4 |
| Loss | 2–6 | Jun 2023 | Lyon, France |
Clay | Hendrik Jebens |
Manuel Guinard Grégoire Jacq |
4–6, 6–2, [7–10] |
| Win | 3–6 | Aug 2023 | Augsburg, Germany |
Clay | Hendrik Jebens |
Constantin Kouzmine Volodymyr Uzhylovskyi |
6–2, 6–2 |
| Win | 4–6 | Sep 2023 | Como, Italy |
Clay | Hendrik Jebens |
 Filip Bergevi Mick Veldheer |
6–3, 6–4 |
| Win | 5–6 | Sep 2023 | Bad Waltersdorf, Austria |
Clay | Hendrik Jebens |
 Marco Bortolotti Francesco Passaro |
6–1, 6–2 |
| Win | 6–6 | Oct 2023 | Orléans, France |
Hard (i) | Hendrik Jebens |
Henry Patten John-Patrick Smith |
7–6(7–5), 7–6(14–12) |
| Loss | 6–7 | Nov 2023 | Ismaning, Germany |
Carpet (i) | Hendrik Jebens |
Sriram Balaji Andre Begemann |
6–7(4–7), 4–6 |
| Loss | 6–8 | Mar 2024 | Lugano, Switzerland |
Hard (i) | Hendrik Jebens |
Sander Arends Sem Verbeek |
7–6(11–9), 6–7(1–7), [8–10] |
| Win | 7–8 | May 2024 | Mauthausen, Austria |
Clay | Hendrik Jebens |
Ryan Seggerman Patrik Trhac |
6–4, 6–4 |
| Win | 8–8 | Mar 2025 | Naples, Italy |
Clay | Alexander Erler |
Geoffrey Blancaneaux Albano Olivetti |
6–4, 6–4 |
| Loss | 8–9 | Jun 2025 | Sassuolo, Italy |
Clay | Alexander Erler |
Matthew Romios Ryan Seggerman |
6–7(4–7), 6–3, [7–10] |
| Win | 9–9 | May 2026 | Valencia, Spain |
Clay | Robin Haase |
Sander Arends David Pel |
6–4, 6–7(5–7), [11–9] |
ITF Tour finals
Doubles: 11 (5 titles, 6 runner-ups)
| Finals by surface |
|---|
| Hard (1–4) |
| Clay (3–2) |
| Carpet (1–0) |
| Result | W–L | Date | Tournament | Surface | Partner | Opponents | Score |
|---|---|---|---|---|---|---|---|
| Win | 1–0 | Oct 2015 | Ismaning, Germany |
Carpet (i) | Alexander Erler |
Kevin Krawietz Tim Sandkaulen |
2–6, 7–5(7–5), [10–8] |
| Loss | 1–1 | Oct 2021 | M15 Lubbock, United States |
Hard |  Sven Lah |
Sekou Bangoura Gijs Brouwer |
4–6, 6–4, [5–10] |
| Loss | 1–2 | Nov 2021 | M25 Harlingen, United States |
Hard | Gabi Adrian Boitan |
 Francis Alcantara Mark Whitehouse |
6–7(3–7), 7–5, [7–10] |
| Loss | 1–3 | Feb 2022 | M25 Glasgow, United Kingdom |
Hard (i) | Charles Broom |
Gijs Brouwer Aidan McHugh |
6–4, 6–7(1–7), [4–10] |
| Loss | 1–4 | Apr 2022 | M15 Monastir, Tunisia |
Hard | Tim Sandkaulen |
Szymon Kielan Michał Mikuła |
6–7(4–7), 7–6(7–2), [2–10] |
| Win | 2–4 | Apr 2022 | M15 Monastir, Tunisia |
Hard | Charles Broom |
 Li Zhe Bu Yunchaokete |
7–5, 2–6, [10–8] |
| Win | 3–4 | May 2022 | M15 Meerbusch, Germany |
Clay | Tim Sandkaulen |
 Miguel Fernando Pereira Gabriel Roveri Sidney |
7–6(7–5), 6–4 |
| Win | 4–4 | May 2022 | M25 Most, Czech Republic |
Clay | Tim Sandkaulen |
 Marek Gengel David Poljak |
6–3, 4–6, [10–7] |
| Loss | 4–5 | Jun 2022 | M25 Arlon, Belgium |
Clay | Tim Sandkaulen |
Anirudh Chandrasekar Vijay Sundar Prashanth |
6–7(5–7), 4–6 |
| Win | 5–5 | Jul 2022 | M25 Kassel, Germany |
Clay | Tim Sandkaulen |
Tom Gentzsch Leopold Zima |
6–4, 6–2 |
| Loss | 5–6 | Aug 2022 | M25 Wetzlar, Germany |
Clay | Tim Sandkaulen |
 Benjamin Hassan Tristan Lamasine |
4–6, 3–6 |
References
- ↑ "Constantin Frantzen - Overview". ATP Tour.
- ↑ "Constantin Frantzen – Men's Tennis". Baylor University Athletics.
- ↑ "Escobar/Nedovyesov Win Sofia Doubles Title; Nys/Zielinski Retain Metz Crown". ATP Tour. 11 November 2023.
- ↑ "First-time partners & last-minute sign in, Erler/Mies win Kitzbühel crown". ATPTour. 27 July 2024.
- ↑ "Hangzhou Open 2024 tennis: Jeevan Nedunchezhiyan-Vijay Sundar Prashanth win doubles title". olympics.com. 24 September 2024.
- ↑ "Frantzen/Haase win maiden team trophy in Chengdu". ATP Tour. 23 September 2025.