Thomaz Koch has found grass courts difficult, recording 21–26 across 47 matches (44.7%). The numbers point to a surface that has not consistently suited the game — a key area of opportunity on the calendar. Claimed 1 title on grass: Manchester.

At Grand Slam level (Wimbledon): Thomaz Koch has struggled at Grand Slam level on grass: 8–14 (36.4%) in 22 matches. The best-of-five format and elite fields make this the toughest benchmark on this surface.

One final reached on grass, converted into a title — a perfect finals record on this surface. 1 semifinal. 2 quarterfinals.

By format on grass — best-of-five: 9–15 (37.5%); best-of-three: 12–11 (52.2%). Markedly stronger in three-set formats; the win rate drops noticeably in five-setters, which has direct implications for Grand Slam performance on grass.

Best season: 1971 — 5–3 (62.5%) from 8 matches. The best single-season display to date — a useful reference point as the grass record continues to develop.

Thomaz Koch recorded a notable 5-match winning streak on grass — a run that demonstrates consistency across consecutive draws on this surface.