| 2025-09-12 | Davis Cup WG1 R1: SVK vs COL | Hard | RR | 331 |  Adria Soriano Barrera | 121 |  Lukas Klein | 3-6 7-6(5) 7-6(5) | H2H | 3 | 143 | 11 | 6 | 67.0% | 77.5% | 57.1% | 1/2 |
| 2025-01-31 | Davis Cup QLS R1: CRO vs SVK | Hard | RR | 158 |  Duje Ajdukovic | 153 | Lukas Klein | 7-6(4) 6-3 | H2H | 3 | - | - | - | - | - | - | - |
| 2025-01-13 | Australian Open | Hard | R128 | 22 |  Sebastian Korda (22) | 144 | Lukas Klein (Q) | 6-3 0-6 6-3 7-6(6) | H2H | 5 | 147 | 7 | 3 | 60.2% | 64.7% | 55.6% | 6/10 |
| 2024-11-03 | Belgrade | Hard | QF | 31 |  Jiri Lehecka (4) | 153 | Lukas Klein (Q) | 3-6 7-6(3) 6-3 | H2H | 3 | 120 | 11 | 2 | 63.6% | 77.8% | 44.4% | 3/6 |
| 2024-11-03 | Belgrade | Hard | R16 | 153 | Lukas Klein (Q) | 39 |  Tomas Martin Etcheverry (7) | 6-4 7-6(6) | H2H | 3 | 106 | 7 | 2 | 71.2% | 74.5% | 68.4% | 0/1 |
| 2024-11-03 | Belgrade | Hard | R32 | 153 | Lukas Klein (Q) | 77 |  James Duckworth | 6-4 6-2 | H2H | 3 | 77 | 5 | 2 | 60.0% | 70.4% | 61.1% | 2/4 |
| 2024-09-18 | Chengdu | Hard | R16 | 28 |  Nicolas Jarry (3) | 127 | Lukas Klein | 7-6(2) 3-6 6-4 | H2H | 3 | 138 | 19 | 2 | 67.7% | 79.4% | 43.3% | 5/7 |
| 2024-09-18 | Chengdu | Hard | R32 | 127 | Lukas Klein | 94 | Adam Walton | 7-6(3) 6-4 | H2H | 3 | 100 | 12 | 2 | 63.5% | 77.5% | 78.3% | 1/1 |
| 2024-09-10 | Davis Cup Finals RR: GER vs SVK | Hard | RR | 104 |  Maximilian Marterer | 128 | Lukas Klein | 6-4 7-5 | H2H | 3 | 91 | 6 | 0 | 60.7% | 78.4% | 70.8% | 1/1 |
| 2024-09-13 | Davis Cup Finals RR: USA vs SVK | Hard | RR | 149 | Mackenzie McDonald | 128 | Lukas Klein | 6-4 6-3 | H2H | 3 | 76 | 5 | 1 | 61.4% | 65.7% | 72.7% | 2/3 |
