| ITF M25 Hamburg | 10/22 12:55 | 27 | Stefan Kozlov v Raul Brancaccio | 4-6,5-7 | |
| ITF M25 Hamburg | 10/21 10:40 | 26 | Stefan Kozlov v Henri Squire | 6-4,6-1 | |
| ITF M25 Hamburg | 10/19 14:50 | 25 | Stefano Napolitano v Stefan Kozlov | 4-6,2-6 | |
| ITF M25 Rodez | 10/14 13:15 | 25 | Stefan Kozlov v Jurgen Briand | 4-6,2-6 | |
| ITF M25 Porto | 10/03 18:00 | 28 | Nuno Borges v Stefan Kozlov | 6-3,7-5 | |
| ITF M25 Porto | 10/03 12:30 | 27 | [335] Dayne Kelly v Stefan Kozlov [393] | 2-6,2-6 | |
| ITF M25 Porto | 10/01 14:00 | 26 | [393] Stefan Kozlov v Adrian Menendez-Maceiras [256] | 7-5,6-3 | |
| ITF M25 Porto | 09/30 16:10 | 25 | [438] Michail Pervolarakis v Stefan Kozlov [393] | 1-6,4-6 | |
| ITF M15 Castelo Branco | 09/24 14:05 | 26 | Stefan Kozlov v Nicolas M D Alboran | 3-6,4-6 | |
| ITF M15 Castelo Branco | 09/23 17:00 | 25 | Stefan Kozlov v Alexis Musialek | 7-5,6-0 | |
| ITF M25 Plaisir | 09/16 08:00 | 25 | Stefan Kozlov v Daniel Cukierman | 6-1,3-6,1-6 | |
| ITF M15 Sintra | 09/09 10:10 | 25 | Robert Strombachs v Stefan Kozlov | 6-4,6-2 | |
| ATP Delray Beach | 02/18 18:35 | 25 | [367] Stefan Kozlov v Ugo Humbert [44] | 7-6,3-6,1-6 | |
| ATP Delray Beach | 02/16 22:05 | 164 | [370] Stefan Kozlov v Emilio Gomez [150] | 3-6,2-6 | |
| ATP Delray Beach | 02/16 00:10 | 64 | [132] Alex Bolt v Stefan Kozlov [370] | 6-4,4-6,2-6 | |
| Challenger Dallas | 02/04 19:15 | 24 | [368] Stefan Kozlov v Donald Young [292] | 2-6,2-6 | |
| ITF M15 Cancun | 01/22 16:55 | 25 | Stefan Kozlov v Maximiliano Estevez | Retired | |
| Challenger Ann Arbor | 01/11 17:45 | 28 | [431] Stefan Kozlov v Roberto Cid Subervi [259] | 6-7,7-5,3-6 | |
| Challenger Ann Arbor | 01/10 17:40 | 27 | [202] Bjorn Fratangelo v Stefan Kozlov [431] | 6-7,2-6 | |
| Challenger Ann Arbor | 01/09 16:00 | 26 | [364] Brandon Nakashima v Stefan Kozlov [431] | 6-4,3-6,2-6 | |
| Challenger Ann Arbor | 01/07 19:55 | 25 | [431] Stefan Kozlov v Renzo Olivo [263] | 7-6,6-2 | |
| Challenger Ann Arbor | 01/06 19:50 | 24 | [431] Stefan Kozlov v Arthur Rinderknech [323] | 6-3,6-4 | |
| Challenger Champaign | 11/15 16:00 | 27 | [473] Stefan Kozlov v Jeffrey John Wolf [255] | 2-6,2-6 | |
| Challenger Champaign | 11/14 17:00 | 26 | [473] Stefan Kozlov v Evan Song [440] | 6-4,4-6,6-1 | |
| Challenger Champaign | 11/13 21:10 | 25 | [115] Denis Kudla v Stefan Kozlov [473] | 3-6,3-6 | |
| Challenger Champaign | 11/12 00:00 | 24 | Simon Carr v Stefan Kozlov | 2-6,6-4,6-7 | |
| ITF M25 Naples | 11/01 15:55 | 27 | Cristian Rodriguez v Stefan Kozlov | 6-2,6-2 | |
| ITF M25 Naples | 10/31 14:00 | 26 | Sam Riffice v Stefan Kozlov | 2-6,4-6 | |
| ITF M25 Naples | 10/29 18:40 | 25 | Mwendwa Mbithi v Stefan Kozlov | 4-6,3-6 | |
| Challenger Las Vegas | 10/18 18:00 | 27 | Stefan Kozlov v James Duckworth | 2-6,3-6 |
Wikipedia - Stefan Kozlov
Stefan Kozlov (Russian: Стефан Козлов, STEF-ahn KOZ-lov; born February 1, 1998) is an American professional tennis player of Russian descent. He has a career-high ATP ranking of world No. 103 achieved on 18 July 2022 and doubles ranking of world No. 180 on 19 June 2017.
Kozlov made his ATP World Tour debut as a wildcard in 2013 Hall of Fame Tennis Championships at the age of 15. He reached two junior Grand Slam finals in 2014 and finished the year at World No. 3 in the ITF Junior Combined rankings.