| Challenger Charlottesville | 11/07 18:00 | 29 | [224] Stefan Kozlov v Aleksandar Vukic [190] | 6-2,6-3 | |
| Challenger Charlottesville | 11/06 17:35 | 28 | [224] Stefan Kozlov v Jeffrey John Wolf [159] | 6-1,6-7,6-0 | |
| Challenger Charlottesville | 11/05 17:55 | 27 | [349] Emilio Nava v Stefan Kozlov [224] | 4-6,2-6 | |
| Challenger Charlottesville | 11/03 23:55 | 26 | [213] Jason Kubler v Stefan Kozlov [224] | 3-6,1-6 | |
| Challenger Charlottesville | 11/03 01:35 | 25 | [224] Stefan Kozlov v Bjorn Fratangelo [172] | 7-5,6-2 | |
| Challenger Las Vegas | 10/31 19:00 | 29 | [247] Stefan Kozlov v Jeffrey John Wolf [195] | 4-6,4-6 | |
| Challenger Las Vegas | 10/30 21:50 | 28 | [247] Stefan Kozlov v Aleksandar Kovacevic [352] | 6-2,6-4 | |
| Challenger Las Vegas | 10/29 19:35 | 27 | [247] Stefan Kozlov v Emilio Gomez [149] | 7-6,6-4 | |
| Challenger Las Vegas | 10/28 19:35 | 26 | [374] Aidan Mchugh v Stefan Kozlov [247] | 2-6,7-5,6-7 | |
| Challenger Las Vegas | 10/26 20:20 | 25 | [392] Sasikumar Mukund v Stefan Kozlov [247] | 2-6,4-6 | |
| ATP Indian Wells | 10/06 18:00 | 19 | [253] Stefan Kozlov v Christopher Eubanks [194] | 6-2,0-6,5-7 | |
| ATP Indian Wells | 10/05 19:25 | 14 | [165] Jason Jung v Stefan Kozlov [253] | Retired | |
| Challenger Columbus | 09/26 16:55 | 29 | [301] Stefan Kozlov v Max Purcell [189] | 4-6,6-2,6-4 | |
| Challenger Columbus | 09/25 16:00 | 28 | [196] Jeffrey John Wolf v Stefan Kozlov [301] | 6-2,3-6,5-7 | |
| Challenger Columbus | 09/24 15:00 | 27 | [226] Mikael Torpegaard v Stefan Kozlov [301] | 6-2,6-7,4-6 | |
| Challenger Columbus | 09/23 15:00 | 26 | [219] Jason Kubler v Stefan Kozlov [301] | 2-6,5-7 | |
| Challenger Columbus | 09/21 19:45 | 25 | [301] Stefan Kozlov v Mitchell Krueger [156] | 6-0,6-3 | |
| Challenger Cary | 09/14 15:00 | 25 | [301] Stefan Kozlov v Zachary Svajda [476] | Retired | |
| Challenger Kyiv | 09/06 12:00 | 25 | [291] Franco Agamenone v Stefan Kozlov [312] | 6-4,7-5 | |
| Challenger Mallorca | 09/02 16:25 | 26 | [312] Stefan Kozlov v Fernando Verdasco [132] | 6-1,6-7,2-6 | |
| Challenger Mallorca | 08/31 12:55 | 25 | Daniel Rincon v Stefan Kozlov | 3-6,6-1,1-6 | |
| US Open | 08/24 15:00 | 14 | [117] Bernabe Zapata Miralles v Stefan Kozlov [309] | 7-5,1-6,6-3 | |
| Challenger Lexington | 07/29 20:00 | 26 | [322] Stefan Kozlov v Alejandro Tabilo [174] | 2-6,2-6 | |
| Challenger Lexington | 07/27 22:30 | 25 | [217] Christopher Eubanks v Stefan Kozlov [322] | 6-7,6-7 | |
| Challenger Lexington | 07/26 20:55 | 19 | [322] Stefan Kozlov v Edan Leshem [418] | 3-6,7-6,6-1 | |
| Challenger Lexington | 07/25 20:30 | 14 | Stefan Kozlov v Sam Riffice | 6-2,6-3 | |
| Challenger Cary | 07/24 21:25 | 28 | [344] Stefan Kozlov v Ramkumar Ramanathan [227] | 6-1,3-6,1-6 | |
| Challenger Cary | 07/23 23:00 | 27 | [220] Christopher Eubanks v Stefan Kozlov [344] | 7-5,1-6,3-6 | |
| Challenger Cary | 07/21 18:45 | 26 | [344] Stefan Kozlov v Maxime Cressy [149] | 3-6,6-3,6-4 | |
| Challenger Cary | 07/19 23:00 | 25 | [344] Stefan Kozlov v Donald Young [365] | 4-6,6-4,6-4 |
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.