Stefan Koubek has a competitive clay court record of 95–94 across 189 matches (50.3%). The record shows a player capable of competing here, though there is clear room to push the win rate higher. Claimed 1 title on clay: Atlanta.

At Grand Slam level (Roland Garros): Stefan Koubek is 8–9 (47.1%) across 17 Grand Slam matches — below .500, though the elite draw depth at the Slams makes that a notoriously difficult barrier to crack.

ATP Masters 1000 on clay (Monte Carlo, Madrid, Rome): Stefan Koubek has struggled at Masters level on clay: 4–10 (28.6%) in 14 matches. Improving at this level is the clearest path to a stronger overall record on this surface.

2 finals reached on clay — won 1, lost 1 (solid 50% conversion) — consistently getting to finals and winning the majority is a hallmark of elite performers on clay. 6 semifinals. 17 quarterfinals.

vs. Top 10 on clay: 3–9 (25.0%, 12 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: 19–15 (55.9%); best-of-three: 76–79 (49.0%). Slightly better in five-set matches on clay — a positive sign for the Slams specifically.

Peak season: 1999 — 28–14 (66.7%) from 42 matches. That year captures the ceiling of what Stefan Koubek can do on clay when performing at their best and represents the standard to aim for.