Lasse Poertner
2023
| J500Plantation | [11] | 3R |
| J300Bradenton | [9] | 2R |
| J300Sanxenxo | [6] | Quarter |
| Us Open Junior | 1R | |
| J300Collegepark | [12] | 3R |
| J300Bamberg | [8] | Final |
Nation
GER
Age
19 years old (born in 2005)
World Ranking
ATP Ranking　881th
Year-end Junior World Ranking
- Year-end 2023 37th
- Year-end 2022 252th
- Year-end 2021 1067th
Match Details
2023 J500Plantation
| W | 1R | Ivan Ivanov | 6-4 4-6 6-1 |
| W | 2R | Rafael Botran Neutze | 6-1 6-4 |
| L | 3R | Alexander Frusina | 4-6 4-6 |
2023 J300Bradenton
| W | 1R | Rafael Botran Neutze | 6-3 6-0 |
| L | 2R | Ivan Ivanov | 6-2 2-6 2-6 |
2023 J300Sanxenxo
| W | 1R | Vit Kalina | 6-3 6-0 |
| W | 2R | Roger Pascual Ferra | 6-7 6-3 6-2 |
| L | QF | Carlo Alberto Caniato | 3-6 1-6 |
2023 Us Open Junior
| L | 1R | Yi Zhou | 4-6 3-6 |
2023 J300Collegepark
| W | 2R | Danil Panarin | 6-2 1-6 6-2 |
| L | 3R | Charlie Robertson | 4-6 6-2 3-6 |
2023 J300Bamberg
| W | 2R | Zachary Viiala | 6-4 6-4 |
| W | 3R | Pedro Rodrigues | 7-5 6-4 |
| W | QF | Diego Dedura-Palomero | 6-2 6-4 |
| W | SF | Marc Majdandzic | 6-2 6-3 |
| L | F | Luca Preda | 1-6 3-6 |
Junior Tennis Database is a site that summarizes the results of ITF junior tennis tournaments.
Number of registered tournaments: 5774, Number of registered players: 3,011, Number of registered results: 222,093