John van Lottum has found grass courts difficult, recording 13–16 across 29 matches (44.8%). 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): John van Lottum is 5–5 (50.0%) across 10 Grand Slam matches — below .500, though the elite draw depth at the Slams makes that a notoriously difficult barrier to crack.

By format on grass — best-of-five: 5–5 (50.0%); best-of-three: 8–11 (42.1%). Slightly better in five-set matches on grass — a positive sign for the Slams specifically.

Best season: 1998 — 6–4 (60.0%) from 10 matches. The best single-season display to date — a useful reference point as the grass record continues to develop.