| Billie Jean King Cup | 11/12 09:00 | 64 | [194] Petra Marcinko v Anna-Lena Friedsam [145] | 4-6,1-6 | |
| Billie Jean King Cup | 11/11 16:50 | 64 | [194] Petra Marcinko v Jule Niemeier [61] | 6-3,6-2 | |
| ITF W100 Shrewsbury | 11/02 12:20 | 25 | [196] Petra Marcinko v Karolina Muchova [158] | 4-6,3-6 | |
| ITF W80 Poitiers | 10/30 14:30 | 29 | [105] Ysaline Bonaventure v Petra Marcinko [283] | 3-6,6-7 | |
| ITF W80 Poitiers | 10/29 14:20 | 28 | [283] Petra Marcinko v Clara Tauson [140] | Retired | |
| ITF W80 Poitiers | 10/28 12:35 | 27 | [149] Lucrezia Stefanini v Petra Marcinko [283] | 3-6,1-6 | |
| ITF W80 Poitiers | 10/27 07:55 | 26 | Petra Marcinko v Alice Tubello | 6-3,6-3 | |
| ITF W80 Poitiers | 10/25 11:00 | 25 | Amandine Monnot v Petra Marcinko | 0-6,2-6 | |
| ITF W60 Trnava | 10/13 11:40 | 26 | [291] Petra Marcinko v Caty McNally [123] | 6-7,1-6 | |
| ITF W60 Trnava | 10/11 14:40 | 25 | [291] Petra Marcinko v Mariam Bolkvadze [308] | Retired | |
| ITF W60 Trnava | 10/06 10:10 | 26 | [209] Sonay Kartal v Petra Marcinko [294] | 6-3,2-6,6-4 | |
| ITF W60 Trnava | 10/05 09:20 | 25 | [294] Petra Marcinko v Arlinda Rushiti [375] | 6-3,6-2 | |
| WTA Portoroz | 09/13 15:25 | 25 | [110] Cristina Bucsa v Petra Marcinko [301] | 2-6,6-4,6-1 | |
| ITF W25 Tarvisio | 07/01 10:25 | 27 | [285] Dalila Jakupovic v Petra Marcinko [340] | 6-2,6-1 | |
| ITF W25 Tarvisio | 06/30 10:50 | 26 | [314] Veronika Erjavec v Petra Marcinko [340] | 5-7,1-6 | |
| ITF W25 Tarvisio | 06/29 10:55 | 25 | [366] Ilona G Ghioroaie v Petra Marcinko [340] | 1-6,5-7 | |
| ITF W25 Prokuplje | 06/25 08:00 | 28 | [316] Tara Wurth v Petra Marcinko [342] | 6-3,7-5 | |
| ITF W25 Prokuplje | 06/24 09:35 | 27 | [342] Petra Marcinko v Ilona G Ghioroaie [359] | 6-2,7-6 | |
| ITF W25 Prokuplje | 06/23 13:05 | 26 | Petra Marcinko v Daria Lodikova | 6-0,6-3 | |
| ITF W25 Prokuplje | 06/22 15:30 | 25 | Petra Marcinko v Dejana Radanovic | Retired | |
| ITF W60 Caserta | 06/08 11:35 | 25 | [340] Petra Marcinko v Camilla Rosatello [330] | 5-7,6-2,6-7 | |
| WTA Rabat | 05/17 13:55 | 26 | [361] Petra Marcinko v Astra Sharma [144] | 7-5,3-6,3-6 | |
| WTA Rabat | 05/15 13:00 | 25 | [77] Rebecca Peterson v Petra Marcinko [362] | 0-6,6-2,5-7 | |
| ITF W25 Split | 05/05 09:20 | 26 | [388] Petra Marcinko v Yuki Naito [219] | Retired | |
| ITF W25 Split | 05/04 13:50 | 25 | Petra Marcinko v Tina Cvetkovic | 6-1,6-2 | |
| ITF W60 Zagreb | 04/29 08:00 | 28 | [388] Petra Marcinko v Jule Niemeier [110] | 6-7,1-6 | |
| ITF W60 Zagreb | 04/28 07:50 | 27 | [388] Petra Marcinko v Katarina Zavatska [199] | 6-3,6-1 | |
| ITF W60 Zagreb | 04/27 13:35 | 26 | [172] Despina Papamichail v Petra Marcinko [388] | 1-6,3-6 | |
| ITF W60 Zagreb | 04/25 14:50 | 25 | [278] Cristiana Ferrando v Petra Marcinko [388] | 6-4,4-6,5-7 | |
| Billie Jean King Cup | 04/16 07:00 | 1 | Lola Radivojevic v Petra Marcinko | 1-6,6-2,0-6 |