| 2‑Dec‑2019 | M15 Santa Marta | Hard | F | 893 | 611 | (3)Alejandro Gomez Gb42 [COL] d. Barrientos | 4-6 6-1 6-4 | | | | | | | | | |
| 2‑Dec‑2019 | M15 Santa Marta | Hard | SF | 893 | 640 | Barrientos d. (4)Juan Sebastian Gomez [COL] | 6-4 6-1 | | | | | | | | | |
| 2‑Dec‑2019 | M15 Santa Marta | Hard | QF | 893 | 805 | Barrientos d. (6)Alejandro Mendoza [BOL] | 6-4 6-2 | | | | | | | | | |
| 2‑Dec‑2019 | M15 Santa Marta | Hard | R16 | 893 | 426 | Barrientos d. (2)Filip Cristian Jianu [ROU] | 6-7(10) 6-4 2-0 RET | | | | | | | | | |
| 2‑Dec‑2019 | M15 Santa Marta | Hard | R32 | 893 | | Barrientos d. (Q)Federico Juan Aguilar [ARG] | 6-1 6-3 | | | | | | | | | |
| 28‑Oct‑2019 | Shenzhen CH | Hard | R64 | 899 | 234 | Tung Lin Wu [TPE] d. (PR)Barrientos | 6-3 7-5 | | 0.72 | 8.2% | 6.6% | 68.9% | 71.4% | 47.4% | 3/5 | 1:18 |
| 21‑Oct‑2019 | Liuzhou CH | Hard | R32 | 967 | 90 | (1)Prajnesh Gunneswaran [IND] d. (PR)Barrientos | 6-2 6-1 | | 0.46 | 4.2% | 6.3% | 60.4% | 51.7% | 31.6% | 3/8 | 0:48 |
| 21‑Oct‑2019 | Liuzhou CH | Hard | R64 | 967 | 388 | (PR)Barrientos d. Fajing Sun [CHN] | 6-4 3-6 7-6(6) | | 1.11 | 1.8% | 6.4% | 67.3% | 71.6% | 55.6% | 9/11 | 2:48 |
| 14‑Oct‑2019 | Ningbo CH | Hard | R32 | 1200 | 188 | (14)Enrique Lopez Perez [ESP] d. (Alt)Barrientos | 6-4 6-3 | | 0.51 | 0.0% | 2.3% | 76.1% | 59.7% | 42.9% | 9/12 | 1:21 |
| 14‑Oct‑2019 | Ningbo CH | Hard | R64 | 1200 | 263 | (Alt)Barrientos d. Goncalo Oliveira [POR] | 7-5 6-0 | | 1.68 | 1.8% | 1.8% | 73.2% | 65.9% | 73.3% | 0/1 | 1:20 |
| 12‑Aug‑2019 | Portoroz CH | Hard | R64 | 1190 | 429 | Viktor Durasovic [NOR] d. (Q)Barrientos | 6-2 3-6 6-1 | | 0.60 | 1.2% | 7.1% | 69.4% | 55.9% | 50.0% | 10/14 | 1:32 |
| 12‑Aug‑2019 | Portoroz CH | Hard | Q1 | 1190 | 437 | Barrientos d. (1)Alexander Erler [AUT] | 3-6 6-2 6-2 | | 1.42 | 4.4% | 5.9% | 69.1% | 78.7% | 38.1% | 2/4 | 1:32 |
| 5‑Aug‑2019 | Manerbio CH | Clay | R64 | 1194 | 548 | (Q)Fabien Reboul [FRA] d. (PR)Barrientos | 6-4 6-3 | | 0.83 | 1.7% | 3.3% | 73.3% | 56.8% | 50.0% | 7/11 | 1:28 |
| 29‑Jul‑2019 | Segovia CH | Hard | R32 | | 238 | (5)Nicola Kuhn [ESP] d. (PR)Barrientos | 6-4 6-3 | | 0.69 | 0.0% | 3.3% | 67.2% | 65.9% | 50.0% | 4/6 | 1:15 |
| 29‑Jul‑2019 | Segovia CH | Hard | R64 | | 554 | (PR)Barrientos d. Dan Added [FRA] | 6-4 7-5 | | 1.16 | 0.0% | 4.7% | 68.2% | 62.1% | 63.0% | 5/7 | 1:39 |
| 15‑Jul‑2019 | Nur-Sultan CH | Hard | R64 | | 345 | Gastao Elias [POR] d. (PR)Barrientos | 6-1 6-1 | | 0.51 | 0.0% | 5.8% | 67.3% | 48.6% | 35.3% | 4/9 | 1:00 |
| 17‑Jun‑2019 | Blois CH | Clay | R64 | | | (WC)Holger Rune [DEN] d. (PR)Barrientos | 6-1 3-6 6-3 | | 0.89 | 0.0% | 5.4% | 68.5% | 52.4% | 31.0% | 7/15 | 1:35 |
| 15‑Apr‑2019 | Anning CH | Clay | R64 | | 239 | Uladzimir Ignatik [BLR] d. (Alt)Barrientos | 6-2 6-2 | | 0.55 | 1.8% | 0.0% | 77.2% | 50.0% | 38.5% | 5/10 | 1:07 |