Stefan Koubek has found grass courts difficult, recording 8–19 across 27 matches (29.6%). The numbers point to a surface that has not consistently suited the game — a key area of opportunity on the calendar.

At Grand Slam level (Wimbledon): Stefan Koubek has struggled at Grand Slam level on grass: 5–10 (33.3%) in 15 matches. The best-of-five format and elite fields make this the toughest benchmark on this surface.

vs. Top 10 on grass: 0–3 (0.0%, 3 matches). Top 10 opponents have represented a clear ceiling on grass; addressing that deficit is the single biggest lever for improving the overall record here.

By format on grass — best-of-five: 5–10 (33.3%); best-of-three: 3–9 (25.0%). Significantly better in five-set matches — a strong physical profile on grass that tends to tell as matches and tournaments progress.

Best season: 2002 — 3–3 (50.0%) from 6 matches. The best single-season display to date — a useful reference point as the grass record continues to develop.