Jan Kodes has an impressive clay court record of 312–135 across 447 matches (69.8% — strong). A win rate of that calibre over 447 matches is a reliable indicator of genuine quality on this surface. 7 titles on clay: Pittsburgh, St. Petersburg, Roland Garros, Catania, Barcelona, Madrid-2 — a record that reflects consistent ability to close out tournaments on this surface.

At Grand Slam level (Roland Garros): Jan Kodes has been outstanding — 48–14 (77.4%) across 62 matches. Winning more than 7 in 10 Grand Slam matches on clay is the benchmark of an all-time great on this surface.

21 finals reached on clay — won 7, lost 14 (33% conversion) — capable of reaching finals consistently, with room to improve at the decisive moment. 41 semifinals. 59 quarterfinals.

vs. Top 10 on clay: 6–21 (22.2%, 27 matches). Top 10 opponents have represented a clear ceiling on clay; addressing that deficit is the single biggest lever for improving the overall record here.

By format on clay — best-of-five: 112–61 (64.7%); best-of-three: 200–74 (73.0%). Markedly stronger in three-set formats; the win rate drops noticeably in five-setters, which has direct implications for Grand Slam performance on clay.

Dominant season: 1972 — 36–8 (81.8%) from 44 matches. A campaign of 36 wins on clay in a single season is among the best single-season records the surface has seen — the clearest benchmark of what is achievable at peak level.