Stefan Kozlov
all rivalries →| Opponent | W | L | M | Last Played | H2H |
|---|---|---|---|---|---|
| Steve Johnson | 3 | 2 | 5 | Jul 14, 2022 | H2H |
| Sam Querrey | 0 | 2 | 2 | Aug 15, 2017 | H2H |
| Donald Young | 0 | 2 | 2 | Mar 11, 2017 | H2H |
| J.J. Wolf | 0 | 1 | 1 | Sep 22, 2022 | H2H |
| Daniil Medvedev | 0 | 1 | 1 | Aug 31, 2022 | H2H |
H2H data updated: 2026-09-01 00:00 UTC
Stefan Kozlov vs Ramkumar Ramanathan
Compare the head-to-head record, career totals, season-by-season performance, and match log for Stefan Kozlov vs Ramkumar Ramanathan.
Want to explore more matchups? Advanced rivalry search lets you browse current and historical rivalries, unbeaten records, or every matchup for a player.
H2H
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0 main draw meetings
H2H Match Log
| Player | Score | Player | Match Data | Date | Round | Tournament | Category | Surface |
|---|---|---|---|---|---|---|---|---|
| Ramkumar Ramanathan | 6-0 6-1 | Stefan Kozlov | Match data | Jul 25, 2022 | Q1 | Atlanta | ATP 250 | Hard |
| Ramkumar Ramanathan | 6-3 6-2 | Stefan Kozlov | Match data | Feb 19, 2018 | Q1 | Delray Beach Open | ATP 250 | Hard |
2 qualifying meetings shown in the table; qualifying is excluded from the H2H score. Arrows show an edition's recorded category and documented modern equivalent; unresolved editions keep their recorded category. Asterisked totals include editions mapped from documented historical predecessor categories. Mapping details.
Career Comparison
| Player | Current | Peak | Pts | Elo | W | L | Win % | GS | 1000 including documented historical predecessor categories | Finals | 500 including documented historical predecessor categories | 250 including documented historical predecessor categories | Titles |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Stefan Kozlov | #297 | #103 | 558 | 1,673 | 9 | 26 | 25.7% | 0 | 0 | 0 | 0 | 0 | 0 |
| Ramkumar Ramanathan | #1,157 | #111 | 495 | 1,640 | 14 | 27 | 34.1% | 0 | 0 | 0 | 0 | 0 | 0 |
Career Progression by Age
Seasons are aligned by the age each player spent most of that calendar year. GS and Titles are cumulative career totals through that season.
| Age | Stefan Kozlov | Ramkumar Ramanathan | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Yr | W-L | Win % | Rank | Elo | GS | Titles | Yr | W-L | Win % | Rank | Elo | GS | Titles | |
| 15 | 2013 | 0–1 | 0.0% | #1083 | 1,489 | 0 | 0 | — | — | — | — | — | — | — |
| 16 | 2014 | 0–1 | 0.0% | #467 | 1,453 | 0 | 0 | — | — | — | — | — | — | — |
| 17 | 2015 | 0–2 | 0.0% | #351 | 1,420 | 0 | 0 | — | — | — | — | — | — | — |
| 18 | 2016 | 3–2 | 60.0% | #116 | 1,481 | 0 | 0 | — | — | — | — | — | — | — |
| 19 | 2017 | 2–9 | 18.2% | #167 | 1,549 | 0 | 0 | 2014 | 1–1 | 50.0% | #241 | 1,543 | 0 | 0 |
| 20 | 2018 | 0–1 | 0.0% | #316 | 1,528 | 0 | 0 | 2015 | 0–2 | 0.0% | #248 | 1,510 | 0 | 0 |
| 21 | — | — | — | — | — | — | — | 2016 | 2–2 | 50.0% | #227 | 1,475 | 0 | 0 |
| 22 | 2020 | 0–1 | 0.0% | #371 | 1,514 | 0 | 0 | 2017 | 3–4 | 42.9% | #148 | 1,567 | 0 | 0 |
| 23 | 2021 | 0–1 | 0.0% | #159 | 1,550 | 0 | 0 | 2018 | 6–5 | 54.5% | #132 | 1,618 | 0 | 0 |
| 24 | 2022 | 4–8 | 33.3% | #198 | 1,529 | 0 | 0 | 2019 | 2–4 | 33.3% | #174 | 1,561 | 0 | 0 |
| 25 | — | — | — | — | — | — | — | 2020 | 0–1 | 0.0% | #190 | 1,513 | 0 | 0 |
| 26 | — | — | — | — | — | — | — | 2021 | 0–3 | 0.0% | #184 | 1,526 | 0 | 0 |
| 27 | — | — | — | — | — | — | — | 2022 | 0–3 | 0.0% | #434 | 1,497 | 0 | 0 |
| 28 | — | — | — | — | — | — | — | 2023 | 0–1 | 0.0% | #440 | 1,503 | 0 | 0 |
| 29 | — | — | — | — | — | — | — | 2024 | 0–1 | 0.0% | #395 | 1,511 | 0 | 0 |
Surface Results by Age
Seasons are aligned by the age each player spent most of that calendar year. Results cover completed main-draw matches. Bold green marks the higher win percentage when both players have at least 5 matches on that surface at the aligned age.
| Age | Stefan Kozlov | Ramkumar Ramanathan | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Yr | Hard | Clay | Grass | Yr | Hard | Clay | Grass | |||||||||||||||||||
| W | L | M | Win % | W | L | M | Win % | W | L | M | Win % | W | L | M | Win % | W | L | M | Win % | W | L | M | Win % | |||
| 15 | 2013 | — | — | — | — | — | — | — | — | 0 | 1 | 1 | 0.0% | — | — | — | — | — | — | — | — | — | — | — | — | — |
| 16 | 2014 | 0 | 1 | 1 | 0.0% | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| 17 | 2015 | 0 | 2 | 2 | 0.0% | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| 18 | 2016 | — | — | — | — | — | — | — | — | 3 | 2 | 5 | 60.0% | — | — | — | — | — | — | — | — | — | — | — | — | — |
| 19 | 2017 | 0 | 6 | 6 | 0.0% | — | — | — | — | 2 | 3 | 5 | 40.0% | 2014 | 1 | 1 | 2 | 50.0% | — | — | — | — | — | — | — | — |
| 20 | 2018 | — | — | — | — | 0 | 1 | 1 | 0.0% | — | — | — | — | 2015 | 0 | 2 | 2 | 0.0% | — | — | — | — | — | — | — | — |
| 21 | — | — | — | — | — | — | — | — | — | — | — | — | — | 2016 | 2 | 2 | 4 | 50.0% | — | — | — | — | — | — | — | — |
| 22 | 2020 | 0 | 1 | 1 | 0.0% | — | — | — | — | — | — | — | — | 2017 | 1 | 3 | 4 | 25.0% | — | — | — | — | 2 | 1 | 3 | 66.7% |
| 23 | 2021 | 0 | 1 | 1 | 0.0% | — | — | — | — | — | — | — | — | 2018 | 2 | 4 | 6 | 33.3% | — | — | — | — | 4 | 1 | 5 | 80.0% |
| 24 | 2022 | 4 | 6 | 10 | 40.0% | — | — | — | — | 0 | 2 | 2 | 0.0% | 2019 | 1 | 3 | 4 | 25.0% | — | — | — | — | 1 | 1 | 2 | 50.0% |
| 25 | — | — | — | — | — | — | — | — | — | — | — | — | — | 2020 | 0 | 1 | 1 | 0.0% | — | — | — | — | — | — | — | — |
| 26 | — | — | — | — | — | — | — | — | — | — | — | — | — | 2021 | 0 | 3 | 3 | 0.0% | — | — | — | — | — | — | — | — |
| 27 | — | — | — | — | — | — | — | — | — | — | — | — | — | 2022 | 0 | 3 | 3 | 0.0% | — | — | — | — | — | — | — | — |
| 28 | — | — | — | — | — | — | — | — | — | — | — | — | — | 2023 | 0 | 1 | 1 | 0.0% | — | — | — | — | — | — | — | — |
| 29 | — | — | — | — | — | — | — | — | — | — | — | — | — | 2024 | 0 | 1 | 1 | 0.0% | — | — | — | — | — | — | — | — |
| Career | — | 4 | 17 | 21 | 19.0% | 0 | 1 | 1 | 0.0% | 5 | 8 | 13 | 38.5% | — | 7 | 24 | 31 | 22.6% | — | — | — | — | 7 | 3 | 10 | 70.0% |
Performance Progression by Age
Seasons are aligned by the age each player spent most of that calendar year. Sample is shown as matches with detailed serve and return statistics / total main draw matches. Bold green marks the stronger value when both stat samples contain at least 5 matches; lower is better for DFs/M.
| Age | Stefan Kozlov | Ramkumar Ramanathan | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Yr | Sample | Aces/M | DFs/M | 1st Sv% | 1st Pts% | 2nd Pts% | BP Saved% | BP Conv% | Svc Pts% | Ret Pts% | Yr | Sample | Aces/M | DFs/M | 1st Sv% | 1st Pts% | 2nd Pts% | BP Saved% | BP Conv% | Svc Pts% | Ret Pts% | |
| 15 | 2013 | 1/1 | 4.0 | 3.0 | 43.5% | 74.5% | 42.6% | 62.5% | 44.4% | 56.5% | 36.0% | — | —/— | — | — | — | — | — | — | — | — | — |
| 16 | 2014 | 1/1 | 2.0 | 4.0 | 56.4% | 61.3% | 50.0% | 63.6% | 16.7% | 56.4% | 35.5% | — | —/— | — | — | — | — | — | — | — | — | — |
| 17 | 2015 | 2/2 | 0.5 | 3.0 | 44.3% | 48.1% | 35.6% | 27.8% | 67.5% | 41.3% | 42.2% | — | —/— | — | — | — | — | — | — | — | — | — |
| 18 | 2016 | 5/5 | 4.2 | 4.8 | 55.8% | 67.8% | 41.9% | 67.2% | 40.4% | 56.9% | 38.4% | — | —/— | — | — | — | — | — | — | — | — | — |
| 19 | 2017 | 11/11 | 3.6 | 4.1 | 58.0% | 65.2% | 44.1% | 53.2% | 35.0% | 56.5% | 32.9% | 2014 | 2/2 | 4.5 | 7.0 | 50.4% | 66.9% | 37.4% | 53.5% | 55.6% | 52.2% | 37.1% |
| 20 | 2018 | 1/1 | 2.0 | 5.0 | 50.9% | 65.5% | 35.7% | 20.0% | 50.0% | 50.9% | 28.0% | 2015 | 2/2 | 7.0 | 3.0 | 48.3% | 73.5% | 33.7% | 53.0% | 0.0% | 52.9% | 27.2% |
| 21 | — | —/— | — | — | — | — | — | — | — | — | — | 2016 | 4/4 | 5.3 | 2.3 | 63.5% | 73.0% | 54.6% | 34.2% | 44.6% | 66.3% | 35.7% |
| 22 | 2020 | 1/1 | 1.0 | 5.0 | 68.5% | 54.1% | 57.1% | 36.4% | 50.0% | 55.1% | 31.7% | 2017 | 7/7 | 8.7 | 4.1 | 56.8% | 73.7% | 51.2% | 71.7% | 32.3% | 63.7% | 33.8% |
| 23 | 2021 | 1/1 | 1.0 | 1.0 | 76.4% | 54.8% | 61.5% | 42.9% | 25.0% | 56.4% | 32.7% | 2018 | 11/11 | 7.1 | 3.8 | 59.1% | 74.7% | 49.1% | 67.1% | 38.1% | 64.6% | 35.3% |
| 24 | 2022 | 12/12 | 1.6 | 4.8 | 72.4% | 60.0% | 43.6% | 59.6% | 35.7% | 55.2% | 36.0% | 2019 | 6/6 | 8.8 | 4.7 | 65.1% | 73.0% | 43.9% | 46.5% | 31.4% | 62.9% | 33.6% |
| 25 | — | —/— | — | — | — | — | — | — | — | — | — | 2020 | 1/1 | 17.0 | 6.0 | 56.6% | 76.7% | 43.5% | 66.7% | 20.0% | 62.3% | 33.7% |
| 26 | — | —/— | — | — | — | — | — | — | — | — | — | 2021 | 3/3 | 9.7 | 5.0 | 56.5% | 79.9% | 42.6% | 38.9% | 16.7% | 63.6% | 28.0% |
| 27 | — | —/— | — | — | — | — | — | — | — | — | — | 2022 | 3/3 | 8.0 | 4.7 | 65.2% | 72.9% | 48.7% | 64.4% | 30.4% | 63.6% | 31.1% |
| 28 | — | —/— | — | — | — | — | — | — | — | — | — | 2023 | 1/1 | 11.0 | 6.0 | 45.7% | 78.6% | 46.0% | 42.9% | 27.3% | 60.9% | 36.9% |
| 29 | — | —/— | — | — | — | — | — | — | — | — | — | 2024 | 1/1 | 8.0 | 8.0 | 60.0% | 69.2% | 42.3% | 50.0% | 0.0% | 58.5% | 21.7% |
| Career | — | 35/35 | 2.6 | 4.3 | 62.0% | 62.4% | 43.9% | 54.8% | 38.2% | 55.1% | 35.3% | — | 41/41 | 7.9 | 4.3 | 59.0% | 74.0% | 47.0% | 57.0% | 32.0% | 62.7% | 33.4% |
Advanced Statistics Comparison by Age
Seasons are aligned by the age each player spent most of that calendar year. Metrics are precomputed from eligible main-draw results; point-stat values use the available detailed sample. Bold green marks the stronger value when both underlying samples are sufficient. Lower is better for Schedule because a negative value means a tougher schedule. Career Schedule is normalized per 100 matches.
| Age | Stefan Kozlov | Ramkumar Ramanathan | ||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Yr | Elo | P+ | Serve+ | Return+ | PD | TPW% | Hard Elo | Clay Elo | Grass Elo | Set Win % | Set Margin | Dec. Set | Tiebreak | Pressure+ | Schedule | Yr | Elo | P+ | Serve+ | Return+ | PD | TPW% | Hard Elo | Clay Elo | Grass Elo | Set Win % | Set Margin | Dec. Set | Tiebreak | Pressure+ | Schedule | |
| 15 | 2013 | 1490 | 100.2 | -4.35 | +1.56 | 0.828 | 46.1% | — | — | — | 33.3% | -1.33 | 0–1 | 1–0 | — | +0.13 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| 16 | 2014 | 1454 | 100.0 | +0.67 | 0.00 | 0.813 | 45.3% | — | — | — | 0.0% | -3.00 | — | — | — | -0.04 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| 17 | 2015 | 1420 | 101.3 | -5.76 | -0.97 | 0.718 | 41.8% | — | — | — | 0.0% | -3.50 | — | — | — | +0.21 | 2012 | 1483 | 95.2 | — | — | — | — | — | — | — | — | — | — | — | — | — |
| 18 | 2016 | 1481 | 107.5 | -3.43 | +1.33 | 0.891 | 48.1% | — | — | +119 | 54.5% | +0.09 | 1–0 | — | — | -0.03 | 2013 | 1474 | 98.0 | — | — | — | — | — | — | — | — | — | — | — | — | — |
| 19 | 2017 | 1550 | 118.7 | -5.47 | -0.25 | 0.757 | 44.9% | -74 | — | +123 | 21.7% | -1.70 | 2–1 (67%) | 0–3 (0%) | — | +0.21 | 2014 | 1544 | 114.1 | -1.99 | -2.63 | 0.776 | 45.6% | — | — | — | 40.0% | -0.60 | 1–0 | — | — | -0.10 |
| 20 | 2018 | 1528 | 106.2 | +0.19 | -0.20 | 0.570 | 40.2% | — | — | — | 0.0% | -3.50 | — | — | — | -0.08 | 2015 | 1511 | 101.2 | -2.47 | -3.37 | 0.578 | 41.8% | — | — | — | 0.0% | -3.50 | — | — | — | +0.09 |
| 21 | 2019 | 1514 | 100.9 | — | — | — | — | — | — | — | — | — | — | — | — | — | 2016 | 1475 | 103.2 | +0.65 | -1.00 | 1.060 | 51.1% | +42 | — | — | 50.0% | +0.10 | 1–1 | 1–0 | — | +0.40 |
| 22 | 2020 | 1514 | 104.1 | -1.24 | +2.90 | 0.705 | 43.9% | — | — | — | 33.3% | -2.33 | 0–1 | 1–0 | — | -0.06 | 2017 | 1567 | 117.9 | +0.61 | -1.11 | 0.930 | 48.9% | -29 | — | +102 | 47.1% | -0.12 | 1–2 (33%) | 1–2 (33%) | — | +0.45 |
| 23 | 2021 | 1550 | 110.6 | +2.69 | +0.42 | 0.749 | 44.9% | — | — | — | 0.0% | -3.00 | — | — | — | +0.04 | 2018 | 1619 | 118.2 | -0.54 | -1.31 | 0.996 | 49.9% | -46 | — | +123 | 54.2% | +0.21 | 1–1 | 1–0 | — | +0.39 |
| 24 | 2022 | 1530 | 118.4 | -4.38 | +0.86 | 0.803 | 45.9% | +20 | — | — | 32.3% | -1.48 | 2–0 | 1–1 | — | -0.54 | 2019 | 1562 | 112.1 | -1.02 | -0.81 | 0.907 | 48.1% | -48 | — | — | 37.5% | -0.88 | 2–2 (50%) | 2–2 (50%) | — | +0.49 |
| 25 | 2023 | 1458 | 91.9 | — | — | — | — | — | — | — | — | — | — | — | — | — | 2020 | 1513 | 95.2 | -2.03 | -2.56 | 0.893 | 48.8% | — | — | — | 33.3% | -0.33 | 0–1 | — | — | +0.05 |
| 26 | 2024 | 1433 | 92.7 | — | — | — | — | — | — | — | — | — | — | — | — | — | 2021 | 1527 | 111.0 | -2.40 | -1.77 | 0.771 | 44.9% | -26 | — | — | 14.3% | -2.14 | 0–1 | 1–1 | — | +0.12 |
| 27 | 2025 | 1436 | 101.4 | — | — | — | — | — | — | — | — | — | — | — | — | — | 2022 | 1497 | 107.8 | -1.44 | -1.57 | 0.853 | 47.2% | -9 | — | — | 25.0% | -1.00 | 0–2 | 0–2 | — | +0.69 |
| 28 | 2026 | 1418 | 97.5 | — | — | — | — | — | — | — | — | — | — | — | — | — | 2023 | 1503 | 101.4 | -0.17 | -3.99 | 0.943 | 48.2% | — | — | — | 33.3% | -0.67 | 0–1 | — | — | +0.09 |
| 29 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 2024 | 1512 | 101.4 | -0.54 | -4.11 | 0.522 | 40.8% | — | — | — | 0.0% | -3.00 | — | 0–1 | — | +0.06 |
| Career | — | 1674 | 113.0 | -4.10 | +0.48 | 0.784 | 45.4% | -15 | — | +121 | 28.4% | -1.58 | 5–3 (63%) | 3–4 (43%) | 104.8 | -0.46 | — | 1640 | 114.6 | -0.69 | -1.55 | 0.895 | 48.1% | -22 | — | +115 | 39.4% | -0.60 | 6–11 (35%) | 6–8 (43%) | 97.7 | +6.66 |
Career Rivalries
Each player's five most-played main-draw opponents. The current matchup is highlighted when it appears in a player's top five.
Ramkumar Ramanathan
all rivalries →| Opponent | W | L | M | Last Played | H2H |
|---|---|---|---|---|---|
| Steve Johnson | 0 | 2 | 2 | Aug 4, 2021 | H2H |
| Marcel Granollers | 1 | 1 | 2 | Jan 3, 2019 | H2H |
| Aleksandr Shevchenko | 0 | 1 | 1 | Oct 4, 2024 | H2H |
| Pedro Martinez | 0 | 1 | 1 | Jan 5, 2023 | H2H |
| Rio Noguchi | 0 | 1 | 1 | Oct 6, 2022 | H2H |