| ITF W60 Rancho Santa Fe | 10/15 16:55 | 27 | Polona Hercog v Elvina Kalieva | 4-6,3-6 | |
| ITF W60 Rancho Santa Fe | 10/14 19:35 | 26 | Polona Hercog v Ellie Douglas | 6-4,6-2 | |
| ITF W60 Rancho Santa Fe | 10/12 19:40 | 25 | Polona Hercog v Jessica Failla | 6-7,6-3,7-5 | |
| WTA Indian Wells | 10/07 19:55 | 23 | [65] Anastasija Sevastova v Polona Hercog [123] | 3-6,6-2,6-0 | |
| US Open - Femenino | 08/31 22:30 | 23 | [11] Petra Kvitova v Polona Hercog [86] | 6-1,6-2 | |
| WTA Cleveland | 08/25 00:35 | 26 | [74] Irina-Camelia Begu v Polona Hercog [85] | 7-6,7-5 | |
| WTA Cleveland | 08/23 18:10 | 25 | [342] Maria Mateas v Polona Hercog [85] | 3-6,2-6 | |
| WTA Cincinnati | 08/14 14:00 | 14 | [87] Polona Hercog v Marie Bouzkova [74] | 6-4,2-6,3-6 | |
| WTA Montreal | 08/08 15:00 | 19 | [62] Tereza Martincova v Polona Hercog [85] | 7-5,6-3 | |
| WTA Montreal | 08/07 15:00 | 14 | [142] Harmony Tan v Polona Hercog [85] | 2-6,3-6 | |
| Wimbledon - Femenino | 06/28 14:30 | 23 | [77] Polona Hercog v Danielle Collins [48] | 6-4,3-6,2-6 | |
| WTA Eastbourne | 06/19 11:25 | 14 | [36] Shuai Zhang v Polona Hercog [73] | 6-1,6-3 | |
| WTA Birmingham | 06/15 15:20 | 25 | [35] Daria Kasatkina v Polona Hercog [73] | 4-6,6-3,6-3 | |
| Open de Francia - Femenino | 06/04 15:45 | 25 | [73] Polona Hercog v Marketa Vondrousova [21] | 3-6,3-6 | |
| Open de Francia - Femenino | 06/02 11:45 | 24 | [73] Polona Hercog v Caroline Garcia [58] | 7-5,6-4 | |
| Open de Francia - Femenino | 05/31 09:00 | 23 | [17] Kiki Bertens v Polona Hercog [73] | 1-6,6-3,4-6 | |
| WTA Belgrado | 05/17 13:00 | 25 | [69] Leylah Fernandez v Polona Hercog [73] | 7-5,6-1 | |
| WTA Roma | 05/10 12:40 | 24 | [19] Maria Sakkari v Polona Hercog [74] | 7-6,3-6,6-2 | |
| WTA Roma | 05/09 09:00 | 19 | [113] Sara Errani v Polona Hercog [73] | 2-6,3-6 | |
| WTA Roma | 05/08 08:00 | 14 | [289] Lucia Bronzetti v Polona Hercog [73] | 4-6,3-6 | |
| WTA Madrid | 04/30 14:30 | 24 | [73] Polona Hercog v Jelena Ostapenko [50] | 3-6,1-6 | |
| WTA Madrid | 04/28 14:10 | 15 | [70] Bernarda Pera v Polona Hercog [73] | 6-4,5-7,6-4 | |
| WTA Madrid | 04/27 15:15 | 14 | [122] Yafan Wang v Polona Hercog [73] | 4-6,2-6 | |
| WTA Estambul | 04/20 11:40 | 25 | [115] Vera Zvonareva v Polona Hercog [73] | 6-3,6-3 | |
| ITF W60 Oeiras | 04/18 09:30 | 29 | [76] Polona Hercog v Clara Burel [177] | Walkover | |
| ITF W60 Oeiras | 04/17 14:05 | 28 | [76] Polona Hercog v Anhelina Kalinina [164] | 6-3,3-6,6-3 | |
| ITF W60 Oeiras | 04/17 08:50 | 27 | [76] Polona Hercog v Lucia Bronzetti [301] | 6-3,6-2 | |
| ITF W60 Oeiras | 04/16 12:00 | 26 | Polona Hercog v Alexandra Dulgheru | 6-4,1-6,6-4 | |
| ITF W60 Oeiras | 04/15 13:05 | 25 | Polona Hercog v Ekaterine Gorgodze | Walkover | |
| WTA Dubai | 03/08 09:30 | 24 | [77] Misaki Doi v Polona Hercog [57] | 6-2,4-6,6-3 |