| 2021-10-18 | Moscow | Hard | R32 | 61 |  Pedro Martinez | 82 |  Guido Pella (PR) | 6-2 RET | H2H | 3 | 50 | 0 | 1 | 48.0% | 75.0% | 46.2% | 1/2 |
| 2021-10-04 | Indian Wells Masters | Hard | R64 | 19 | Roberto Bautista Agut (15) | 80 | Guido Pella | 7-5 6-3 | H2H | 3 | 116 | 2 | 3 | 61.6% | 71.1% | 39.3% | 9/12 |
| 2021-10-04 | Indian Wells Masters | Hard | R128 | 80 | Guido Pella | 56 |  Soonwoo Kwon | 1-6 6-3 6-4 | H2H | 3 | 131 | 6 | 2 | 69.2% | 56.8% | 42.4% | 15/20 |
| 2021-09-18 | Davis Cup WG1 R1: ARG vs BLR | Clay | RR | 82 | Guido Pella | - |  Erik Arutiunian | 6-1 6-2 | H2H | 3 | 71 | 3 | 1 | 76.9% | 67.5% | 41.7% | 3/4 |
| 2021-08-30 | US Open | Hard | R64 | 50 |  Frances Tiafoe | 85 | Guido Pella | 6-1 6-2 7-5 | H2H | 5 | 112 | 11 | 0 | 71.2% | 78.8% | 38.1% | 0/2 |
| 2021-08-30 | US Open | Hard | R128 | 85 | Guido Pella | 38 |  Filip Krajinovic (32) | 6-7(2) 6-3 6-2 6-2 | H2H | 5 | 198 | 28 | 5 | 66.4% | 72.2% | 55.0% | 7/9 |
| 2021-08-23 | Winston-Salem | Hard | R64 | 59 |  Jordan Thompson | 84 | Guido Pella | 6-1 1-6 6-3 | H2H | 3 | 127 | 11 | 5 | 55.7% | 82.1% | 48.4% | 2/4 |
| 2021-08-16 | Cincinnati Masters | Hard | R16 | 5 |  Alexander Zverev (3) | 93 | Guido Pella (PR) | 6-2 6-3 | H2H | 3 | 73 | 8 | 3 | 67.5% | 85.2% | 69.2% | 0/0 |
| 2021-08-16 | Cincinnati Masters | Hard | R32 | 93 | Guido Pella (PR) | 36 |  Fabio Fognini | 6-1 7-5 | H2H | 3 | 89 | 7 | 1 | 70.3% | 65.4% | 54.5% | 6/7 |
| 2021-08-16 | Cincinnati Masters | Hard | R64 | 93 | Guido Pella (PR) | 19 |  David Goffin (15) | 6-3 6-3 | H2H | 3 | - | 4 | 1 | 72.2% | 66.7% | 60.0% | 2/3 |
