| 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 Briand, Jurgen | 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] Kelly, Dayne v Stefan Kozlov [393] | 2-6,2-6 | |
| ITF M25 Porto | 10/01 14:00 | 26 | [393] Stefan Kozlov v Menendez-Maceiras, Adrian [256] | 7-5,6-3 | |
| ITF M25 Porto | 09/30 16:10 | 25 | [438] Pervolarakis, Michail 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 Musialek, Alexis | 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 Young, Donald [292] | 2-6,2-6 | |
| ITF M15 Cancun | 01/22 16:55 | 25 | Stefan Kozlov v Estevez Maximiliano | Retired | |
| Ann Arbor, USA | 01/11 17:45 | 28 | [431] Stefan Kozlov v Roberto Cid Subervi [259] | 6-7,7-5,3-6 | |
| Ann Arbor, USA | 01/10 17:40 | 27 | [202] Fratangelo, Bjorn v Stefan Kozlov [431] | 6-7,2-6 | |
| Ann Arbor, USA | 01/09 16:00 | 26 | [364] Brandon Nakashima v Stefan Kozlov [431] | 6-4,3-6,2-6 | |
| Ann Arbor, USA | 01/07 19:55 | 25 | [431] Stefan Kozlov v Renzo Olivo [263] | 7-6,6-2 | |
| Ann Arbor, USA | 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 Wolf, Jeffrey John [255] | 2-6,2-6 | |
| Challenger Champaign | 11/14 17:00 | 26 | [473] Stefan Kozlov v Song, Evan [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 | Carr, Simon v Stefan Kozlov | 2-6,6-4,6-7 | |
| ITF - M25 Naples | 11/01 15:55 | 27 | Rodriguez, Cristian v Stefan Kozlov | 6-2,6-2 | |
| ITF - M25 Naples | 10/31 14:00 | 26 | Riffice, Sam 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.