Marcos Ondruska has found grass courts difficult, recording 13–17 across 30 matches (43.3%). 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 (Wimbledon): Marcos Ondruska has struggled at Grand Slam level on grass: 3–6 (33.3%) in 9 matches. The best-of-five format and elite fields make this the toughest benchmark on this surface.

By format on grass — best-of-five: 5–7 (41.7%); best-of-three: 8–10 (44.4%). Slightly stronger in three-set contests on grass, though the five-set record is still respectable.

Best season: 1993 — 4–3 (57.1%) from 7 matches. The best single-season display to date — a useful reference point as the grass record continues to develop.