Stefan Kozlov

Stefan Kozlov (born 1 February 1998 in Skopje, Republic of Macedonia) is an American tennis player. He is the son of Russian parents and his father is a tennis coach.
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 grand slam success led him to a career high junior ranking of No. 2. Kozlov also competed at the U18 National Championship, finishing in 3rd place in the Singles tournament and winning the Doubles tournament with Noah Rubin. With that victory, they earned a wild card into the main draw of the 2014 US Open. He capped off the year by winning the prestigious Orange Bowl junior tournament to avenge a loss in the final the previous year.

In 2015, Kozlov reached the final of the U18 National Championship, where he lost to Frances Tiafoe in a five set thriller.

Early years

Kozlov made his ATP World Tour debut as a wild card at the Newport tournament in 2013 and lost in the first round to Michał Przysiężny in 3 sets. 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 would lose to fellow American Sam Querrey who was ranked 45. He has also reached 7 career ITF Futures finals and won 4 of them.

2016: First ATP win and Challenger title

In April, Kozlov reached the final at the Open de Guadeloupe to propel him into the Top 250 of the ATP rankings for the first time. In June, he won his first career ATP level match as a wild card at the Rosmalen Grass Court Championships in Den Bosch by defeating Yoshihito Nishioka. He then upset No. 39 Steve Johnson, the highest ranked player he ever defeated. Towards the end of the season, Kozlov reached a second Challenger final on the year at Suzhou to break into the Top 150. He finally won his first career Challenger event at the last tournament of the year in Columbus, becoming the 5th American teenager to win a Challenger in 2016 (joining Taylor Fritz, Frances Tiafoe, Reilly Opelka, and Michael Mmoh).

Singles (5–6)

Outcome	No.	Date	Tournament	Surface	Opponent	Score
Runner-up	1.	000000002014-09-29-000029 September 2014	Sacramento, USA	Hard	Sam Querrey	3–6, 4–6
Runner-up	2.	000000002015-05-10-000010 May 2015	Orange Park, USA	Hard	Darian King	2–6, 6–3, 0–6
Runner-up	3.	000000002015-05-17-000017 May 2015	Mexico City, Mexico	Hard	Iván Endara	1–6, 6–7(3–7)
Runner-up	4.	000000002015-10-18-000018 October 2015	Minsk, Belarus	Hard (i)	Dzmitry Zhyrmont	1–6, 4–6
Winner	5.	000000002015-10-25-000025 October 2015	Minsk, Belarus	Hard (i)	Dzmitry Zhyrmont	6–1, 7–6(7–1)
Winner	6.	000000002016-01-10-000010 January 2016	Los Angeles, USA	Hard	Philip Bester	7–6(9–7), 6–7(3–7), 6–3
Winner	7.	000000002016-03-13-000013 March 2016	Sherbrooke, Canada	Hard (i)	Lloyd Glasspool	4–6, 6–4, 6–4
Runner-up	8.	000000002016-04-10-000010 April 2016	Le Gosier, Guadeloupe	Hard	Malek Jaziri	2–6, 4–6
Winner	9.	000000002016-04-17-000017 April 2016	Little Rock, USA	Hard	Eric Quigley	6–7(3–7), 6–3, 7–6(12–10)
Runner-up	10.	000000002016-10-30-000030 October 2016	Suzhou, China	Hard	Lu Yen-hsun	0–6, 1–6
Winner	11.	000000002016-11-27-000027 November 2016	Columbus, USA	Hard (i)	Tennys Sandgren	6–1, 2–6, 6–2

Doubles (2–1)

Outcome	No.	Date	Tournament	Surface	Partner	Opponent	Score
Winner	1.	000000002013-11-15-000015 November 2013	Bradenton, USA	Clay	Sekou Bangoura	Devin McCarthy Tommy Mylnikov	6–2, 6–4
Runner-up	2.	000000002014-05-23-000023 May 2014	Vic, Spain	Clay	Noah Rubin	Sergio Martos Gornés Pol Toledo Bagué	2–6, 5–7
Winner	3.	February 1, 2015	Maui, United States	Hard	Jared Donaldson	Chase Buchanan Rhyne Williams	6–3, 6–4

Boys' Singles

Outcome	Year	Championship	Surface	Opponent	Score
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

Boys' Doubles

Outcome	Year	Championship	Surface	Partner	Opponents	Score
Runner-up	2014	Wimbledon	Grass	Andrey Rublev	Orlando Luz Marcelo Zormann	4–6, 6–3, 6–8