Kazakhstan: Nur-Sultan - Singles - Main |
| 1/16-finals | Harris G. | Gerasimov E. | 1:2 (3:6, 6:3, 63:7) | details | 27.10.2020 |
Belgium: Antwerp - Singles - Main |
| Quarter-finals | Harris G. | Humbert U. | 0:2 (3:6, 62:7) | details | 23.10.2020 |
| 1/8-finals | Fritz T. | Harris G. | 0:2 (5:7, 63:7) | details | 22.10.2020 |
| 1/16-finals | Moutet C. | Harris G. | 0:2 (5:7, 2:6) | details | 20.10.2020 |
Belgium: Antwerp - Singles - Qualification |
| Final | Coria F. | Harris G. | 0:2 (4:6, 0:6) | details | 19.10.2020 |
| Semi-finals | Khan Z. | Harris G. | 0:2 (61:7, 2:6) | details | 18.10.2020 |
Germany: Cologne - Singles - Main |
| Quarter-finals | Zverev A. | Harris G. | 2:1 (6:4, 3:6, 6:0) | details | 16.10.2020 |
| 1/8-finals | Harris G. | Johnson S. | 2:0 (7:65, 7:62) | details | 14.10.2020 |
| 1/16-finals | Edmund K. | Harris G. | 0:2 (5:7, 61:7) | details | 13.10.2020 |
Germany: Cologne - Singles - Qualification |
| Final | Harris G. | Giron M. | 2:1 (2:6, 6:4, 6:2) | details | 11.10.2020 |
| Semi-finals | Harris G. | Gojowczyk P. | 2:1 (2:6, 6:1, 6:3) | details | 10.10.2020 |
Italy: Parma - Singles - Main |
| 1/16-finals | Harris G. | Petrovic D. | CAN. | details | 06.10.2020 |
France: French Open - Singles - Main |
| 1/32-finals | Harris G. | Berrettini M. | 1:3 (4:6, 6:4, 2:6, 3:6) | details | 01.10.2020 |
| 1/64-finals | Harris G. | Popyrin Al. | 3:0 (6:4, 6:4, 7:67) | details | 29.09.2020 |
Italy: Forli - Singles - Main |
| Semi-finals | Musetti L. | Harris G. | 1:1 RET. (4:6, 6:0, 4:1) | details | 25.09.2020 |
| Quarter-finals | Caruso S. | Harris G. | 0:2 (61:7, 5:7) | details | 24.09.2020 |
| 1/8-finals | Fratangelo B. | Harris G. | 0:2 (66:7, 4:6) | details | 23.09.2020 |
| 1/16-finals | Arnaboldi A. | Harris G. | 1:2 (64:7, 6:1, 64:7) | details | 21.09.2020 |
Italy: Rome - Singles - Qualification |
| Quarter-finals | Sugita Y. | Harris G. | 2:0 (6:4, 6:2) | details | 12.09.2020 |
USA: US Open - Singles - Main |
| 1/32-finals | Harris G. | Goffin D. | 1:3 (66:7, 6:4, 1:6, 4:6) | details | 02.09.2020 |
| 1/64-finals | Harris G. | Cecchinato M. | 3:0 (6:4, 7:5, 6:2) | details | 01.09.2020 |
USA: Cincinnati - Singles - Main |
| 1/32-finals | Harris G. | Fritz T. | 0:2 (1:6, 3:6) | details | 22.08.2020 |
USA: Cincinnati - Singles - Qualification |
| Final | Harris G. | Martin A. | 2:1 (6:2, 4:6, 6:1) | details | 21.08.2020 |
| Semi-finals | Ymer M. | Harris G. | 0:2 (5:7, 5:7) | details | 20.08.2020 |
World: Davis Cup - World Group I - Singles - Preliminary |
| | Dzumhur D. | Harris G. | 1:0 RET. (6:1, 2:1) | details | 07.03.2020 |
| | Basic M. | Harris G. | 0:2 (5:7, 2:6) | details | 06.03.2020 |
United Arab Emirates: Dubai - Singles - Main |
| 1/16-finals | Harris G. | Gasquet R. | 0:2 (65:7, 4:6) | details | 24.02.2020 |
United Arab Emirates: Dubai - Singles - Qualification |
| Final | Harris G. | Ruusuvuori E. | 0:0 RET. (1:0) | details | 23.02.2020 |
| Semi-finals | Harris G. | Fabbiano T. | 2:1 (5:7, 6:4, 6:3) | details | 22.02.2020 |
France: Marseille - Singles - Qualification |
| Semi-finals | Harris G. | Benchetrit E. | 0:2 (3:6, 4:6) | details | 16.02.2020 |
Australia: Australian Open - Singles - Main |
| 1/64-finals | Schwartzman D. | Harris G. | 3:0 (6:4, 6:2, 6:2) | details | 21.01.2020 |
Australia: Adelaide - Singles - Main |
| Final | Harris G. | Rublev A. | 0:2 (3:6, 0:6) | details | 18.01.2020 |
| Semi-finals | Paul T. | Harris G. | 1:2 (4:6, 7:63, 3:6) | details | 17.01.2020 |
| Quarter-finals | Carreno-Busta P. | Harris G. | 0:2 (3:6, 3:6) | details | 16.01.2020 |
| 1/8-finals | Djere L. | Harris G. | 0:2 (65:7, 3:6) | details | 15.01.2020 |
| 1/16-finals | Harris G. | Garin C. | 2:1 (7:65, 3:6, 6:4) | details | 13.01.2020 |
Australia: ATP Cup - Singles - Main |
| | Simon G. | Harris G. | 2:1 (2:6, 6:2, 6:2) | details | 08.01.2020 |
| | Paire B. | Harris G. | CAN. | details | 08.01.2020 |
| | Harris G. | Jarry N. | 2:0 (6:4, 6:4) | details | 06.01.2020 |
| | Lajovic D. | Harris G. | 2:1 (3:6, 7:64, 6:3) | details | 04.01.2020 |
Slovakia: Bratislava 2 - Singles - Main |
| Quarter-finals | Kolar Z. | Harris G. | 2:1 (65:7, 7:67, 6:4) | details | 08.11.2019 |
| 1/8-finals | Maden Y. | Harris G. | 1:2 (6:1, 3:6, 3:6) | details | 07.11.2019 |
| 1/16-finals | Rosol L. | Harris G. | 0:2 (65:7, 65:7) | details | 06.11.2019 |
Germany: Eckental - Singles - Main |
| Semi-finals | Darcis S. | Harris G. | 2:0 (6:2, 6:4) | details | 02.11.2019 |
| Quarter-finals | Harris G. | Lacko L. | 2:1 (65:7, 6:3, 6:3) | details | 01.11.2019 |
| 1/8-finals | Harris G. | Otte O. | 2:1 (4:6, 6:4, 7:63) | details | 31.10.2019 |