J. Jahn is a ATP tennis player. Current clay-court ELO 1426 (45-49). Recent form: 9-6 over the last 15 matches.
| Date | | Opponent | Score | Event |
| Sept. 24, 2023 |
L |
M. Echargui |
0 - 2 |
Braga Challenger Men · clay |
| Sept. 17, 2023 |
L |
T. Stodder |
2 - 0 |
Bad Waltersdorf Challenger Men · clay |
| Sept. 5, 2023 |
L |
H. Laaksonen |
1 - 2 |
Tulln Challenger Men · clay |
| Sept. 4, 2023 |
W |
M. Kasnikowski |
0 - 2 |
Tulln Challenger Men · clay |
| Sept. 3, 2023 |
W |
K. Wehnelt |
0 - 2 |
Tulln Challenger Men · clay |
| Sept. 1, 2023 |
L |
M. Houkes |
0 - 2 |
ITF M25 Oldenzaal Men · clay |
| Aug. 31, 2023 |
W |
M. Vankan |
2 - 0 |
ITF M25 Oldenzaal Men · clay |
| Aug. 29, 2023 |
W |
A. Deckers |
1 - 2 |
ITF M25 Oldenzaal Men · clay |
| Aug. 25, 2023 |
L |
V. Bielinskyi |
1 - 2 |
ITF M25 Poznan Men · clay |
| Aug. 24, 2023 |
W |
J. Szajrych |
2 - 0 |
ITF M25 Poznan Men · clay |
| Aug. 23, 2023 |
W |
D. Kellovsky |
2 - 0 |
ITF M25 Poznan Men · clay |
| Aug. 19, 2023 |
L |
T. Legout |
2 - 1 |
ITF M25 Koksijde Men · clay |
| Aug. 18, 2023 |
W |
M. Vankan |
2 - 0 |
ITF M25 Koksijde Men · clay |
| Aug. 17, 2023 |
W |
A. Boureau |
2 - 0 |
ITF M25 Koksijde Men · clay |
| Aug. 15, 2023 |
W |
N. Bruna |
2 - 0 |
ITF M25 Koksijde Men · clay |