13‑Nov‑2023 | M25 Columbus OH | Hard | R16 | 930 | 847 | (5)Shunsuke Mitsui [JPN] d. Altamirano | 5-7 6-3 6-3 | | | | | | | | | |
13‑Nov‑2023 | M25 Columbus OH | Hard | R32 | 930 | | Altamirano d. (WC)Nikita Filin [USA] | 4-6 6-1 6-2 | | | | | | | | | |
6‑Nov‑2023 | Calgary CH | Hard | Q1 | 946 | 559 | (5)Olukayode Alafia Damina Ayeni [USA] d. Altamirano | 7-6(6) 6-4 | | 1.02 | 3.9% | 3.9% | 50.6% | 84.6% | 39.5% | 2/5 | |
30‑Oct‑2023 | M25 Edmonton | Hard | R16 | 964 | 536 | (5)Giles Hussey [GBR] d. Altamirano | 6-4 6-3 | | | | | | | | | |
30‑Oct‑2023 | M25 Edmonton | Hard | R32 | 964 | 867 | Altamirano d. Brayden Schnur [CAN] | 6-4 2-6 6-4 | | | | | | | | | |
23‑Oct‑2023 | M25 Harlingen TX | Hard | R16 | 964 | | Marcus Mcdaniel [USA] d. Altamirano | 6-2 6-3 | | | | | | | | | |
23‑Oct‑2023 | M25 Harlingen TX | Hard | R32 | 964 | 1401 | Altamirano d. Joao Vitor Goncalves Ceolin [BRA] | 6-4 6-4 | | | | | | | | | |
18‑Sep‑2023 | M25 Takasaki | Hard | SF | 1215 | 652 | (4)Makoto Ochi [JPN] d. (Q)Altamirano | 6-7(7) 6-1 6-2 | | | | | | | | | |
18‑Sep‑2023 | M25 Takasaki | Hard | QF | 1215 | 754 | (Q)Altamirano d. (7)Kazuki Nishiwaki [JPN] | 6-3 6-1 | | | | | | | | | |
18‑Sep‑2023 | M25 Takasaki | Hard | R16 | 1215 | 1884 | (Q)Altamirano d. (Q)Hiroyasu Ehara [JPN] | 6-4 6-1 | | | | | | | | | |
18‑Sep‑2023 | M25 Takasaki | Hard | R32 | 1215 | 1274 | (Q)Altamirano d. (Q)Hayato Matsuoka [JPN] | 5-7 6-4 6-2 | | | | | | | | | |
11‑Sep‑2023 | M25 Sapporo | Hard | R32 | 1200 | | (2)Yuki Mochizuki [JPN] d. (Q)Altamirano | 7-6(3) 6-4 | | | | | | | | | |
4‑Sep‑2023 | M25 Hong Kong | Hard | R32 | 1465 | 812 | Kazuki Nishiwaki [JPN] d. (Q)Altamirano | 6-3 7-5 | | | | | | | | | |
28‑Aug‑2023 | M25 Hong Kong | Hard | R16 | 1465 | 456 | (2)Ajeet Rai [NZL] d. (Q)Altamirano | 6-3 6-3 | | | | | | | | | |
28‑Aug‑2023 | M25 Hong Kong | Hard | R32 | 1465 | 2058 | (Q)Altamirano d. (WC)Nathan Anthony Barki [INA] | 6-2 4-6 6-2 | | | | | | | | | |
21‑Aug‑2023 | M15 Nakhon Si Thammarat | Hard | QF | 1463 | 615 | (2)Palaphoom Kovapitukted [THA] d. (Q)Altamirano | 6-3 5-7 6-4 | | | | | | | | | |
21‑Aug‑2023 | M15 Nakhon Si Thammarat | Hard | R16 | 1463 | 1193 | (Q)Altamirano d. (Q)Siddhant Banthia [IND] | 7-5 6-2 | | | | | | | | | |
21‑Aug‑2023 | M15 Nakhon Si Thammarat | Hard | R32 | 1463 | 1024 | (Q)Altamirano d. Taiyo Yamanaka [JPN] | 3-6 6-1 6-4 | | | | | | | | | |
3‑Jul‑2023 | M25 The Hague | Clay | R16 | 1626 | 587 | (PR)Guy Den Ouden [NED] d. (LL)Altamirano | 7-6(4) 3-6 6-2 | | | | | | | | | |
3‑Jul‑2023 | M25 The Hague | Clay | R32 | 1626 | 1516 | (LL)Altamirano d. (Q)Oskar Jansson [SWE] | 6-2 6-4 | | | | | | | | | |
19‑Jun‑2023 | M15 Saarlouis | Clay | R16 | 1918 | 665 | Joao Fonseca [BRA] d. (Q)Altamirano | 6-2 6-3 | | | | | | | | | |
19‑Jun‑2023 | M15 Saarlouis | Clay | R32 | 1918 | 562 | (Q)Altamirano d. (5)Andres Andrade [ECU] | 7-6(9) 2-6 6-3 | | | | | | | | | |
29‑May‑2023 | M25 Carnac | Clay | R32 | | 283 | (1)Titouan Droguet [FRA] d. (Q)Altamirano | 6-1 6-2 | | | | | | | | | |
22‑May‑2023 | M15 Pazardzhik | Clay | R16 | | 678 | Matyas Fuele [HUN] d. (Q)Altamirano | 7-5 6-4 | | | | | | | | | |
22‑May‑2023 | M15 Pazardzhik | Clay | R32 | | | (Q)Altamirano d. (WC)Vadym Konovchuk [UKR] | 3-6 6-3 7-5 | | | | | | | | | |
15‑May‑2023 | M15 Antalya | Clay | R32 | | 963 | Paul Woerner [GER] d. (Q)Altamirano | 7-5 7-6(1) | | | | | | | | | |
23‑Jan‑2023 | M15 Edmond OK | Hard | R32 | | 492 | (3)Ezekiel Clark [USA] d. (WC)Altamirano | 6-0 4-6 6-2 | | | | | | | | | |
16‑Jan‑2023 | M15 Ithaca NY | Hard | R32 | | 561 | (5)Nathan Ponwith [USA] d. (WC)Altamirano | 6-4 6-1 | | | | | | | | | |