Robert Machan has found clay courts difficult, recording 13–26 across 39 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): Robert Machan has struggled at Grand Slam level on clay: 1–4 (20.0%) in 5 matches. The best-of-five format and elite fields make this the toughest benchmark on this surface.

By format on clay — best-of-five: 3–10 (23.1%); best-of-three: 10–16 (38.5%). Markedly stronger in three-set formats; the win rate drops noticeably in five-setters, which has direct implications for Grand Slam performance on clay.

Best season: 1973 — 6–7 (46.2%) from 13 matches. The best single-season display to date — a useful reference point as the clay record continues to develop.