Stefan Kozlov
ATP · World No. 296 · USA · Right-handed, two-handed backhand · 183 cm · 79 kg
Turned pro 2013 · Coach: Andrei Kozlov
At a glance
Elo
1629
Hard Elo
1596
Clay Elo
1561
Grass Elo
1501
Last 52w win%
59%
Last 10
5-5
Tiebreak win%
55%
Deciding-set win%
58%
Serve & return profile
Return-first: wins by breaking rather than overpowering on serve. Converts break chances at a high rate.
Serve / return map
vs 896 tour pros
Strengths vs tour
Career percentile · tick = tour median
Serve points won60%45th
Return points won42%91th
Ace rate3.4%29th
Double-fault discipline4.9%19th
Break points saved56%34th
Break points won43%79th
Serve anatomy
1st serve in63%
1st serve won66%
2nd serve won48%
Surface splits
Serve & return points won, break-point save & conversion, and ace rate, broken out by surface. Win% is heat-shaded against a 50% baseline. Toggle the window: career, last 52 weeks, or this season.
| Surface | M | W-L | Win% | Serve% | Return% | Ace% | BP Sv% | BP Cv% |
|---|---|---|---|---|---|---|---|---|
| All | 145 | 80-65 | 55% | 60% | 42% | 3.4% | 56% | 43% |
| Hard | 107 | 60-47 | 56% | 60% | 41% | 3.6% | 57% | 43% |
| Clay | 32 | 17-15 | 53% | 58% | 43% | 2.8% | 56% | 44% |
| Grass | 6 | 3-3 | 50% | 58% | 40% | 3.3% | 51% | 46% |
Recent matches
| Date | Tournament | Surf | Odds | R | Opponent | Score |
|---|---|---|---|---|---|---|
| Jul 14, 2026 | Pozoblanco Challenger · Challenger 75 | Hard | 2.33 | L | Yi Zhou | 6-3 3-6 6-4 |
| Jul 10, 2026 | Newport Challenger · Challenger 125 | Grass | 3.26 | L | Jacob Fearnley | 3-6 6-3 6-2 |
| Jul 9, 2026 | Newport Challenger · Challenger 125 | Grass | 4.80 | W | Yibing Wu | 6-4 2-6 6-4 |
| Jul 7, 2026 | Newport Challenger · Challenger 125 | Grass | 1.20 | W | — | 6-4 6-2 |
| Jul 5, 2026 | Newport Challenger · Challenger 125 | Grass | 1.73 | W | — | 7-6(3) 5-7 6-3 |
| May 12, 2026 | Valencia Challenger · Challenger 175 | Clay | 2.11 | L | — | 7-5 6-4 |
| May 11, 2026 | Valencia Challenger · Challenger 175 | Clay | — | W | — | 6-2 6-1 |
| Apr 22, 2026 | Savannah Challenger · Challenger 75 | Clay | — | L | Nick Hardt | 6-2 2-6 6-0 |
| Apr 20, 2026 | Savannah Challenger · Challenger 75 | Clay | — | W | Daniil Glinka | 6-2 6-3 |
| Apr 14, 2026 | Tallahassee Challenger · Challenger 75 | Clay | — | L | — | 7-6(3) 6-2 |
| Apr 13, 2026 | Tallahassee Challenger · Challenger 75 | Clay | 2.33 | W | Kilian Feldbausch | 6-1 4-6 7-6(2) |
| Apr 12, 2026 | Tallahassee Challenger · Challenger 75 | Clay | 1.30 | W | — | 6-0 6-4 |
| Apr 8, 2026 | Mexico City Challenger · Challenger 125 | Clay | 2.58 | L | James Duckworth | 6-3 6-2 |
| Apr 6, 2026 | Mexico City Challenger · Challenger 125 | Clay | — | W | — | 6-3 6-1 |
| Mar 31, 2026 | San Luis Potosi Challenger · Challenger 75 | Clay | — | L | — | 6-3 7-6(7) |
| Mar 24, 2026 | Morelia Challenger · Challenger 125 | Hard | — | L | — | 6-2 6-2 |
| Mar 19, 2026 | Morelos Challenger · Challenger 75 | Hard | — | L | Michael Mmoh | 7-5 6-2 |
| Mar 17, 2026 | Morelos Challenger · Challenger 75 | Hard | 1.10 | W | — | 6-4 6-4 |
| Mar 11, 2026 | Phoenix Challenger · Challenger 175 | Hard | 1.84 | L | — | 6-2 4-6 6-3 |
| Mar 10, 2026 | Phoenix Challenger · Challenger 175 | Hard | 1.71 | W | — | 6-1 3-6 6-4 |
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