Marcos Daniel has found clay courts difficult, recording 22–37 across 59 matches (37.3%). 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): Marcos Daniel has struggled at Grand Slam level on clay: 1–5 (16.7%) in 6 matches. The best-of-five format and elite fields make this the toughest benchmark on this surface.

4 quarterfinals on clay, including one run to the semifinal — regularly reaching that stage is a solid baseline, with the next step being to break through to the final rounds more often.

By format on clay — best-of-five: 5–7 (41.7%); best-of-three: 17–30 (36.2%). Slightly better in five-set matches on clay — a positive sign for the Slams specifically.

Best season: 2008 — 8–8 (50.0%) from 16 matches. The best single-season display to date — a useful reference point as the clay record continues to develop.