Piero Toci has found clay courts difficult, recording 15–30 across 45 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): Piero Toci has struggled at Grand Slam level on clay: 2–5 (28.6%) in 7 matches. The best-of-five format and elite fields make this the toughest benchmark on this surface.

By format on clay — best-of-five: 3–4 (42.9%); best-of-three: 12–26 (31.6%). Significantly better in five-set matches — a strong physical profile on clay that tends to tell as matches and tournaments progress.

Best season: 1968 — 5–7 (41.7%) from 12 matches. The best single-season display to date — a useful reference point as the clay record continues to develop.