William Jansen
2022
| US OPEN JUNIOR | 2R | |
| WIMBLEDON JUNIOR | 2R | |
| J1 ROEHAMPTON | Quarter | |
| J1 NOTTINGHAM | Semi | |
| J2 ALDERSHOT | [4] | Win |
| J3 LOUGHBOROUGH-2 | [2] | Final |
| J3 LOUGHBOROUGH | [2] | Final |
| J1 SALINAS | 1R | |
| J1 BARRANQUILLA | [15] | 3R |
| J1 SANJOSE | 1R |
2021
| J3 AIZKRAUKLE | [4] | 1R |
| J3 ADANA | [3] | 1R |
| J4 HARARE-4 | [2] | Win |
| J4 HARARE-3 | [2] | Semi |
| J3 BARCELONA | Quarter | |
| J4 KRANJ | [2] | Quarter |
| WIMBLEDON JUNIOR | 1R | |
| J1 ROEHAMPTON | 1R | |
| J3 MEGRINE | Quarter | |
| J5 SFAX | Semi | |
| J4 SOUSSE | 2R | |
| J5 DAKAR-2 | [2] | Quarter |
| J5 DAKAR | [2] | 2R |
| J5 NAIROBI | [3] | Quarter |
| J4 NAIROBI-2 | 1R | |
| J4 NAIROBI | 2R |
2020
| J5 HARARE-2 | [4] | Final |
| J5 HARARE | [4] | Semi |
| J5 JOHANNESBURG | Semi | |
| J5 JELGAVA | 2R | |
| J4 LARNACA-3 | Quarter | |
| J4 LANARCA-3 | 2R |
Nation
GBR
World Ranking
ATP Ranking　1385th
Year-end Junior World Ranking
- Year-end 2022 79th
- Year-end 2021 212th
- Year-end 2020 713th
- Year-end 2019 2108th
Rival
Ethan Denzel Sibanda (2-1)
Luca Pow (0-2)
Viktor Frydrych (2-0)
Nicholas Godsick (1-1)
Michael Zheng (1-1)
Match Details
2022 US OPEN JUNIOR
| W | 1R | Jeremy Jin | 6-1 6-3 |
| L | 2R | Michael Zheng | 2-6 5-7 |
2022 WIMBLEDON JUNIOR
| W | 1R | Juan Carlos Prado Angelo | 7-5 7-6 |
| L | 2R | Gilles Arnaud Bailly | 4-6 3-6 |
2022 J1 ROEHAMPTON
| W | 1R | Ignacio Buse | 6-3 7-5 |
| W | 2R | Jaden Weekes | 6-2 5-7 7-6 |
| W | 3R | Michael Zheng | 6-3 6-1 |
| L | QF | Alex Michelsen | 6-3 5-7 3-6 |
2022 J1 NOTTINGHAM
| W | 1R | Luka Novakovic | 3-6 7-5 6-3 |
| W | 2R | Nicholas Godsick | 7-5 6-0 |
| W | 3R | Ron Ellouck | 6-2 6-4 |
| W | QF | Gabriel Debru | 7-6 7-6 |
| L | SF | Bor Artnak | 6-7 3-6 |
2022 J2 ALDERSHOT
| W | 1R | James Beaven | 6-4 7-6 |
| W | 2R | Henry Jefferson | 7-5 6-2 |
| W | QF | Sean Daryabeigi | 6-2 6-0 |
| W | SF | Louis Bowden | 3-6 7-5 6-4 |
| W | F | Phoenix Weir | 6-2 6-3 |
2022 J3 LOUGHBOROUGH-2
| W | 1R | Markus Molder | 6-2 6-2 |
| W | 2R | Viktor Frydrych | 6-1 6-2 |
| W | QF | Jamie Diack | 6-1 6-2 |
| W | SF | Benjamin Gusic Wan | 6-2 6-1 |
| L | F | Luca Pow | 1-6 0-6 |
2022 J3 LOUGHBOROUGH
| W | 1R | Kacper Szymkowiak | 7-6 6-1 |
| W | 2R | Fabio Nestola | 6-1 6-1 |
| W | QF | Viktor Frydrych | 6-1 6-2 |
| W | SF | Hugo Coquelin | 6-0 6-0 |
| L | F | Luca Pow | 3-6 4-6 |
2022 J1 SALINAS
| L | 1R | Enrique Pena | 2-6 3-6 |
2022 J1 BARRANQUILLA
| W | 2R | Felipe Pinzon Moreno | 6-3 6-2 |
| L | 3R | Nicholas Godsick | 2-6 4-6 |
2022 J1 SANJOSE
| L | 1R | Preston Stearns | 2-6 1-6 |
2021 J3 AIZKRAUKLE
| L | 1R | Georg Eduard Israelan | 6-1 3-6 2-6 |
2021 J3 ADANA
| L | 1R | Tuncay Duran | 2-6 1-6 |
2021 J4 HARARE-4
| W | 1R | Mengezi Denzel Awakhiwe Sibanda | 6-0 6-0 |
| W | 2R | Ronan Tashinga Mtisi | 6-0 6-0 |
| W | QF | Ethan Denzel Sibanda | 6-2 3-6 6-3 |
| W | SF | Aayush P Bhat | 6-3 6-4 |
| W | F | Federico Cina | 7-5 6-4 |
2021 J4 HARARE-3
| W | 1R | Malachi Harry | 6-1 6-1 |
| W | 2R | Joseph Townes | 6-1 6-1 |
| W | QF | Ethan Denzel Sibanda | 6-0 7-5 |
| L | SF | Federico Cina | 1-6 4-6 |
2021 J3 BARCELONA
| W | 1R | Oliver Ojakaar | 7-6 4-6 6-3 |
| W | 2R | Georgios Nouchakis | 6-1 6-2 |
| L | QF | Jay Dylan Hara Friend | 6-3 3-6 3-6 |
2021 J4 KRANJ
| W | 2R | Ziga Svec | 6-2 6-1 |
| W | 3R | Job Japelj | 6-1 6-2 |
| L | QF | Giacomo Nosei | 4-6 6-2 3-6 |
2021 WIMBLEDON JUNIOR
| L | 1R | Bruno Kuzuhara | 5-7 7-6 3-6 |
2021 J1 ROEHAMPTON
| L | 1R | Aleksander Orlikowski | 1-6 6-3 3-6 |
2021 J3 MEGRINE
| W | 1R | William Jucha | 6-3 6-0 |
| W | 2R | Yassine Dlimi | - - - |
| L | QF | Wissam Abderrahman | 4-1 1-4 2-4 |
2021 J5 SFAX
| W | 1R | Rodrigo Deleu | 6-3 6-2 |
| W | 2R | Youssef Labbene | 6-2 6-2 |
| W | QF | Gabriel Berner | 6-2 6-1 |
| L | SF | Pablo Trochu | 5-7 2-6 |
2021 J4 SOUSSE
| W | 1R | Rodrigo Deleu | 6-2 6-1 |
| L | 2R | Seydina Andre | 2-6 2-6 |
2021 J5 DAKAR-2
| W | 1R | John Gabelic | 6-4 6-0 |
| W | 2R | Massimo Giunta | 6-3 6-2 |
| L | QF | Maxime Dubouch | 6-3 0-6 4-6 |
2021 J5 DAKAR
| W | 1R | Tiago Boschmans | 6-4 6-1 |
| L | 2R | Nicolas Recoura | 4-6 0-3 |
2021 J5 NAIROBI
| W | 1R | Ofer Hacohen | 7-6 6-4 |
| W | 2R | Clement Bergantz | - - - |
| L | QF | Theo Herrmann | 3-6 3-6 |
2021 J4 NAIROBI-2
| L | 1R | Seydina Andre | 2-6 3-6 |
2021 J4 NAIROBI
| W | 1R | Eytan Miessen | 6-2 6-1 |
| L | 2R | Etienne Marty | 1-6 2-6 |
2020 J5 HARARE-2
| W | 1R | Shane Tapera | 6-0 6-2 |
| W | 2R | Marshall Hulett | 6-1 6-2 |
| W | QF | Takura Mhwandagara | 6-2 6-1 |
| W | SF | Aayush P Bhat | 6-3 6-0 |
| L | F | Andreas Scott | 6-7 0-4 |
2020 J5 HARARE
| W | 1R | Lyle Zaloumis | 6-1 6-2 |
| W | 2R | Marshall Hulett | 6-2 6-0 |
| W | QF | Mats Herremans | 6-4 6-3 |
| L | SF | Ethan Denzel Sibanda | 4-6 4-6 |
2020 J5 JOHANNESBURG
| W | 1R | Anro Nel | 6-4 7-5 |
| W | 2R | Francois Van Wyk | 6-7 6-4 7-5 |
| W | QF | Sam Kydd Baumgartner | 6-2 6-3 |
| L | SF | Mikaeel Woodman | 7-5 4-6 1-5 |
2020 J5 JELGAVA
| W | 1R | Daniil Piatrouski | 6-3 7-6 |
| L | 2R | Edas Butvilas | 6-2 3-6 5-7 |
2020 J4 LARNACA-3
| W | 1R | Christos Zonias | 6-1 6-0 |
| W | 2R | Luc Koenig | 6-3 6-2 |
| L | QF | Jan Kobierski | 4-6 3-6 |
2020 J4 LANARCA-3
| W | 1R | Petros Pieros | 4-6 6-1 6-4 |
| L | 2R | Pablo Trochu | 5-7 6-7 |
Junior Tennis Database is a site that summarizes the results of ITF junior tennis tournaments.
Number of registered tournaments: 10193, Number of registered players: 6,472, Number of registered results: 375,648