Mark Knowles has found clay courts difficult, recording 9–18 across 27 matches (33.3%). 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 (Roland Garros): 1–1 across just 2 matches — still very early days at this level on clay.

ATP Masters 1000 on clay (Monte Carlo, Madrid, Rome): Mark Knowles has struggled at Masters level on clay: 1–3 (25.0%) in 4 matches. Improving at this level is the clearest path to a stronger overall record on this surface.

By format on clay — best-of-five: 6–10 (37.5%); best-of-three: 3–8 (27.3%). Significantly better in five-set matches — a strong physical profile on clay that tends to tell as matches and tournaments progress.

Best season: 1995 — 2–4 (33.3%) from 6 matches. The best single-season display to date — a useful reference point as the clay record continues to develop.