Stadium: Center Court Round: 25 Ground: Hardcourt outdoor
| Challenger Nottingham Qual | 2018/06/10 12:25 | Frederik Nielsen v Austin Krajicek | 6-3,7-6 |
| Challenger Nottingham Qual | 2018/06/09 14:35 | Tiran Sanghera v Austin Krajicek | 3-6,2-6 |
| Challenger Puerto Vallarta | 2018/04/30 20:30 | Austin Krajicek v Edan Leshem | 3-6,4-6 |
| Challenger Mexico City | 2018/04/10 21:20 | Juan Ignacio Londero v Austin Krajicek | 7-5,6-1 |
| Challenger Mexico City Qual | 2018/04/09 19:00 | Austin Krajicek v Gonzalo Escobar | 7-5,2-6,7-6 |
| Challenger Mexico City Qual | 2018/04/08 18:55 | Austin Krajicek v Alexios Halebian | 6-4,6-0 |
| Challenger Mexico City Qual | 2018/04/07 19:30 | Austin Krajicek v Shalva Dzhanashia | 6-3,6-3 |
| Challenger San Luis Potosi | 2018/03/29 22:15 | Austin Krajicek v Jose Hernandez-Fernandez | 0-6,2-6 |
| Challenger Winnetka Qual | 2018/07/09 16:50 | Emil Reinberg v Collin Altamirano | 3-6,4-6 |
| Challenger Winnetka Qual | 2018/07/08 16:35 | Logan Smith v Collin Altamirano | 2-6,3-6 |
| Challenger Winnetka Qual | 2018/07/07 15:00 | Sam Riffice v Collin Altamirano | 6-7,6-3,4-6 |
| ITF USA F19 | 2018/07/05 17:30 | Collin Altamirano v Reese Stalder | 3-6,1-6 |
| ITF USA F19 | 2018/07/04 14:00 | Collin Altamirano v Samuel Beren | 6-2,6-3 |
| ITF USA F17 | 2018/06/26 19:00 | Collin Altamirano v Jeffrey John Wolf | 4-6,5-7 |
| ITF Singapore F2 | 2018/05/26 03:00 | Takuto Niki v Collin Altamirano | 6-7,3-6 |
| ITF Singapore F2 | 2018/05/25 03:00 | Kazuki Nishiwaki v Collin Altamirano | 7-5,2-6,3-6 |