Stadium: Court 1 Round: 24 Ground: Hardcourt indoor
| Challenger Dallas | 2020/02/04 03:00 | Harrison, Ryan v Brandon Nakashima | 3-6,4-6 |
| Newport Beach, USA | 2020/01/27 19:35 | Redlicki, Michael v Harrison, Ryan | 7-5,6-2 |
| US Open, New York, USA | 2019/08/19 16:15 | Dominik Koepfer v Harrison, Ryan | 6-1,6-1 |
| Atlanta, USA | 2019/07/21 18:20 | Troicki, Viktor v Harrison, Ryan | 6-4,5-7,6-7 |
| Open de France | 2019/05/21 09:35 | Harrison, Ryan v Pavlasek, Adam | 3-6,7-6,6-7 |
| ATP - Houston | 2019/04/10 18:05 | Henri Laaksonen v Harrison, Ryan | 6-4,7-5 |
| ATP - Houston | 2019/04/08 20:00 | Harrison, Ryan v Karlovic, Ivo | 6-3,6-4 |
| ATP - Miami | 2019/03/18 18:20 | Ymer, Mikael v Harrison, Ryan | 6-1,6-3 |
| Newport Beach, USA | 2020/01/27 21:35 | Collin Altamirano v Thai-Son Kwiatkowski | 1-6,3-6 |
| ITF M25 Rancho Santa Fe | 2020/01/17 18:45 | Collin Altamirano v Geoffrey Blancaneaux | 0-6,7-6,5-7 |
| ITF M25 Rancho Santa Fe | 2020/01/16 18:00 | Collin Altamirano v Sebastian Fanselow | 6-1,6-1 |
| ITF M25 Rancho Santa Fe | 2020/01/15 17:30 | Collin Altamirano v Gomez, Lucas | 6-0,2-6,6-2 |
| Los Angeles, Singles M-ITF-USA-01A | 2020/01/10 18:00 | Alexander Ritschard v Collin Altamirano | 6-1,3-6,6-3 |
| Los Angeles, Singles M-ITF-USA-01A | 2020/01/09 20:45 | Alex Rybakov v Collin Altamirano | 6-3,3-6,4-6 |
| Los Angeles, Singles M-ITF-USA-01A | 2020/01/07 20:50 | Smith, Roy v Collin Altamirano | 7-6,1-6,4-6 |
| ITF M15 Austin | 2019/11/24 16:50 | Collin Altamirano v Jacob Fearnley | 4-6,6-4,6-4 |