|Country (sports)||United States|
|Residence||Pembroke Pines, Florida, United States|
|Born||1 February 1998|
Skopje, Republic of Macedonia
|Height||1.83 m (6 ft 0 in)|
|Plays||Right-handed (two-handed backhand)|
|Career record||5–15 (25%)|
|Highest ranking||No. 115 (20 February 2017)|
|Current ranking||No. 199 (18 June 2018)|
|Grand Slam Singles results|
|Australian Open||Q3 (2018)|
|French Open||Q2 (2017)|
|Wimbledon||Q2 (2017, 2018)|
|US Open||Q2 (2014)|
|Highest ranking||No. 180 (19 June 2017)|
|Current ranking||No. 180 (19 June 2017)|
|Grand Slam Doubles results|
|US Open||1R (2014)|
|Last updated on: 22 June 2017.|
Kozlov made his ATP World Tour debut as a wild card in Newport at the age of 15. He reached two junior Grand Slam finals in 2014 and finished the year at No. 3 in the ITF Junior Combined rankings.
In 2014, Kozlov reached two junior grand slam finals, where he lost to Alexander Zverev at the Australian Open and Noah Rubin at Wimbledon. This success led him to a career high junior ranking of No. 2. Kozlov also competed at the U18 National Championships, finishing in third place in the singles tournament and winning the doubles tournament with Noah Rubin. With this victory, they earned a wild card into the main draw of the 2014 US Open. He ended the year by winning the Orange Bowl junior tournament.
Kozlov made his ATP World Tour debut as a wild card at the Newport tournament in 2013 and lost in the first round. At the age of 16, he defeated his first Top 100 player in Tim Smyczek to reach his first ATP Challenger final in Sacramento, where he lost to Sam Querrey. He has also reached seven career ITF Futures finals and won four of these finals.
2016: First ATP win and Challenger titleEdit
In April, Kozlov reached the final at the Open de Guadeloupe. In June, he won his first career ATP level match as a wild card at the Rosmalen Grass Court Championships in Den Bosch. Toward the end of the season, Kozlov reached a second Challenger final on the year at Suzhou. He won his first career Challenger event at Columbus.
Challenger and Futures finalsEdit
Singles: 12 (6–6)Edit
|Loss||0–1||Oct 2014||Sacramento, US||Challenger||Hard||Sam Querrey||3–6, 4–6|
|Loss||0–2||May 2015||USA F15, Orange Park||Futures||Hard||Darian King||2–6, 6–3, 0–6|
|Loss||0–3||May 2015||Mexico F3, Mexico City||Futures||Hard||Iván Endara||1–6, 6–7(3–7)|
|Loss||0–4||Oct 2015||Belarus F3, Minsk||Futures||Hard (i)||Dzmitry Zhyrmont||1–6, 4–6|
|Win||1–4||Oct 2015||Belarus F4, Minsk||Futures||Hard (i)||Dzmitry Zhyrmont||6–1, 7–6(7–1)|
|Win||2–4||Jan 2016||USA F1, Los Angeles||Futures||Hard||Philip Bester||7–6(9–7), 6–7(3–7), 6–3|
|Win||3–4||Mar 2016||Canada F2, Sherbrooke||Futures||Hard (i)||Lloyd Glasspool||4–6, 6–4, 6–4|
|Loss||3–5||Apr 2016||Le Gosier, Guadeloupe||Challenger||Hard||Malek Jaziri||2–6, 4–6|
|Win||4–5||Apr 2016||USA F13, Little Rock||Futures||Hard||Eric Quigley||6–7(3–7), 6–3, 7–6(12–10)|
|Loss||4–6||Oct 2016||Suzhou, China||Challenger||Hard||Lu Yen-hsun||0–6, 1–6|
|Win||5–6||Nov 2016||Columbus, US||Challenger||Hard (i)||Tennys Sandgren||6–1, 2–6, 6–2|
|Win||6–6||Oct 2017||Las Vegas, US||Challenger||Hard||Liam Broady||3–6, 7–5, 6–4|
Doubles: 9 (4–5)Edit
|Win||1–0||Nov 2013||USA F31, Bradenton||Futures||Clay||Sekou Bangoura|| Devin McCarthy
|Loss||1–1||May 2014||Spain F10, Vic||Futures||Clay||Noah Rubin|| Sergio Martos Gornés
Pol Toledo Bagué
|Win||2–1||Jan 2015||Maui, US||Challenger||Hard||Jared Donaldson|| Chase Buchanan
|Loss||2–2||Oct 2015||Croatia F18, Solin||Futures||Clay||Nino Serdarušić|| Zdeněk Kolář
|4–6, 6–2, [6–10]|
|Win||3–2||Mar 2016||Canada F1, Gatineau||Futures||Hard (i)||Kaichi Uchida|| Sebastian Fanselow
|Win||4–2||Jul 2016||Winnetka, US||Challenger||Hard||John-Patrick Smith|| Sekou Bangoura
|Loss||4–3||Sep 2016||Cary, US||Challenger||Hard||Austin Krajicek|| Philip Bester
|Loss||4–4||Oct 2016||Ningbo, China||Challenger||Hard||Akira Santillan|| Jonathan Eysseric
|Loss||4–5||Apr 2017||Sarasota, US||Challenger||Clay||Peter Polansky|| Scott Lipsky
Junior Grand Slam finalsEdit
|Runner-up||2014||Australian Open||Hard||Alexander Zverev||3–6, 0–6|
|Runner-up||2014||Wimbledon||Grass||Noah Rubin||6–4, 4–6, 3–6|
|Runner-up||2014||Wimbledon||Grass||Andrey Rublev|| Orlando Luz
|4–6, 6–3, 6–8|
- "The pronunciation by Stefan Kozlov himself". ATPWorldTour.com. Retrieved 2018-01-10.
- RacquetComedy (2015-01-27). "AFULL INTERVIEW: Stefan Kozlov". YouTube. Retrieved 2018-01-25.
- Michelle Kaufman (9 July 2013). "Floridian Kozlov on the rise". Miami Herald. Retrieved 27 October 2017.
- "Stefan Kozlov junior profile". Retrieved 27 October 2017.
- Michelle Kaufman (14 December 2014). "Kozlov wins long-awaited Orange Bowl". Miami Herald. Retrieved 27 October 2017.