| Challenger Bordeaux | 05/10 15:00 | 25 | [94] Jaume Munar v Stefan Kozlov [118] | 6-2,6-3 | |
| Challenger Savannah | 04/26 21:30 | 25 | Jose Pereira v Stefan Kozlov | 6-1,6-0 | |
| Challenger Mexico City | 04/04 21:55 | 25 | [271] Gerald Melzer v Stefan Kozlov [122] | Retired | |
| Challenger Pereira | 03/29 16:55 | 25 | [264] Nicolas Mejia v Stefan Kozlov [120] | 6-1,6-1 | |
| ATP Miami | 03/21 15:25 | 14 | [164] Mitchell Krueger v Stefan Kozlov [121] | 6-2,6-2 | |
| ATP Indian Wells | 03/10 00:00 | 19 | [86] Holger N Rune v Stefan Kozlov [121] | 6-4,6-2 | |
| ATP Indian Wells | 03/09 02:35 | 14 | Sebastian Sec v Stefan Kozlov | 3-6,7-6,2-6 | |
| ATP Acapulco | 02/24 02:00 | 26 | [5] Rafael Nadal v Stefan Kozlov [130] | 6-0,6-3 | |
| ATP Acapulco | 02/22 03:35 | 25 | [33] Grigor Dimitrov v Stefan Kozlov [130] | 6-7,7-5,3-6 | |
| ATP Acapulco | 02/21 02:55 | 19 | [85] Oscar Otte v Stefan Kozlov [151] | 6-1,0-6,7-6 | |
| ATP Acapulco | 02/20 04:10 | 14 | Stefan Kozlov v Steve Johnson | 6-4,6-3 | |
| ATP Delray Beach | 02/18 18:00 | 27 | [41] Tommy Paul v Stefan Kozlov [151] | 6-3,6-1 | |
| ATP Delray Beach | 02/16 18:05 | 26 | [99] Steve Johnson v Stefan Kozlov [151] | 1-6,3-6 | |
| ATP Delray Beach | 02/15 19:30 | 25 | [151] Stefan Kozlov v Emilio Gomez [149] | 4-6,7-5,6-3 | |
| ATP Delray Beach | 02/15 19:30 | 25 | Stefan Kozlov v Jenson Brooksby | Cancelled | |
| ATP Delray Beach | 02/13 18:00 | 19 | [152] Stefan Kozlov v Bjorn Fratangelo [154] | Retired | |
| ATP Delray Beach | 02/12 17:00 | 14 | [152] Stefan Kozlov v Go Soeda [281] | 7-5,6-2 | |
| Challenger Columbus | 01/26 15:00 | 26 | [169] Stefan Kozlov v Dominic Stephan Stricker [241] | 6-4,4-6,3-6 | |
| Challenger Columbus | 01/24 23:20 | 25 | Alexander Bernard v Stefan Kozlov | 2-6,1-6 | |
| Australian Open | 01/19 03:45 | 24 | [169] Stefan Kozlov v Matteo Berrettini [7] | 1-6,6-4,4-6,1-6 | |
| Australian Open | 01/17 01:40 | 23 | [168] Stefan Kozlov v Jiri Vesely [79] | 7-5,6-3,6-4 | |
| ATP Sydney | 01/09 04:15 | 14 | [159] Stefan Kozlov v Denis Kudla [105] | 6-4,6-7,3-6 | |
| Challenger Bendigo | 01/04 01:50 | 25 | [205] Flavio Cobolli v Stefan Kozlov [159] | 6-4,3-6,6-1 | |
| Challenger Champaign | 11/21 17:00 | 29 | [170] Aleksandar Vukic v Stefan Kozlov [187] | 7-5,3-6,4-6 | |
| Challenger Champaign | 11/20 20:35 | 28 | [184] Jeffrey John Wolf v Stefan Kozlov [187] | 2-6,3-6 | |
| Challenger Champaign | 11/19 20:50 | 27 | [187] Stefan Kozlov v Mitchell Krueger [164] | 6-4,6-4 | |
| Challenger Champaign | 11/17 17:25 | 26 | Stefan Kozlov v Keegan Smith | 6-3,6-1 | |
| Challenger Champaign | 11/15 22:30 | 25 | [187] Stefan Kozlov v JC Aragone [355] | 3-6,6-3,6-4 | |
| Challenger Knoxville | 11/12 00:40 | 26 | [358] Aidan Mchugh v Stefan Kozlov [188] | 6-4,6-4 | |
| Challenger Knoxville | 11/10 00:20 | 25 | [172] Aleksandar Vukic v Stefan Kozlov [188] | 3-6,6-4,5-7 |
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.