| 2026-02-06 | Davis Cup WG1 PO: LUX vs UKR | Hard | RR | - |  Alex Knaff | 499 |  Vladyslav Orlov | 7-6(2) 6-2 | H2H | 3 | 93 | 3 | 0 | 60.8% | 83.9% | 80.0% | 0/1 |
| 2025-02-01 | Davis Cup WG1 PO: LUX vs LTU | Hard | RR | 718 | Alex Knaff | 192 |  Vilius Gaubas | 6-4 3-6 6-2 | H2H | 3 | - | - | - | - | - | - | - |
| 2025-09-12 | Davis Cup WG1 R1: CHI vs LUX | Clay | RR | 134 |  Tomas Barrios Vera | 668 | Alex Knaff | 6-1 6-2 | H2H | 3 | 75 | 3 | 1 | 63.4% | 88.5% | 46.7% | 2/2 |
| 2024-09-14 | Davis Cup WG2 R1: NZL vs LUX | Hard | RR | 644 | Alex Knaff | - |  Rubin Statham | 6-3 6-2 | H2H | 3 | 70 | 5 | 2 | 68.9% | 80.6% | 57.1% | 0/1 |
| 2024-09-14 | Davis Cup WG2 R1: NZL vs LUX | Hard | RR | 644 | Alex Knaff | 454 | Kiranpal Pannu | 6-1 6-7(8) 7-5 | H2H | 3 | 170 | 6 | 2 | 60.2% | 69.2% | 65.1% | 8/10 |
| 2024-02-02 | Davis Cup WG1 PO: COL vs LUX | Clay | RR | 411 |  Nicolas Mejia | 500 | Alex Knaff | 6-2 6-3 | H2H | 3 | 82 | 4 | 1 | 69.0% | 72.5% | 55.6% | 3/4 |
| 2024-02-02 | Davis Cup WG1 PO: COL vs LUX | Clay | RR | 500 | Alex Knaff | 593 | Adria Soriano Barrera | 6-4 2-6 6-4 | H2H | 3 | 125 | 2 | 5 | 56.8% | 67.4% | 60.0% | 3/6 |
| 2023-02-04 | Davis Cup WG2 PO: RSA vs LUX | - | RR | 608 | Alex Knaff | 687 |  Alec Beckley | 4-6 6-3 6-3 | H2H | 3 | - | - | - | - | - | - | - |
| 2023-09-15 | Davis Cup WG2 R1: SLO vs LUX | Clay | RR | 486 | Alex Knaff | 616 | SLOBor Artnak | 3-6 7-6(5) 6-2 | H2H | 3 | - | - | - | - | - | - | - |
| 2023-09-15 | Davis Cup WG2 R1: SLO vs LUX | Clay | RR | 457 | SLOBlaz Rola | 486 | Alex Knaff | 6-4 6-2 | H2H | 3 | - | - | - | - | - | - | - |
