Andrew Castle has found hard courts difficult, recording 12–25 across 37 matches (32.4%). The numbers point to a surface that has not consistently suited the game — a key area of opportunity on the calendar. Andrew Castle has reached 1 final without yet claiming a title on hard — one of the finest margins in tennis.

At Grand Slam level (Australian Open & US Open): Andrew Castle has struggled at Grand Slam level on hard: 3–5 (37.5%) in 8 matches. The best-of-five format and elite fields make this the toughest benchmark on this surface.

One final reached on hard, without converting it into a title. That final-round experience is valuable groundwork for going one step further next time. 1 semifinal. 1 quarterfinal.

By format on hard — best-of-five: 4–7 (36.4%); best-of-three: 8–18 (30.8%). Slightly better in five-set matches on hard — a positive sign for the Slams specifically.

Best season: 1988 — 7–11 (38.9%) from 18 matches. The best single-season display to date — a useful reference point as the hard record continues to develop.