Grega Zemlja has found hard courts difficult, recording 21–29 across 50 matches (42.0%). The numbers point to a surface that has not consistently suited the game — a key area of opportunity on the calendar. Grega Zemlja 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): Grega Zemlja has struggled at Grand Slam level on hard: 2–5 (28.6%) in 7 matches. The best-of-five format and elite fields make this the toughest benchmark on this surface.

ATP Masters 1000 on hard (Indian Wells, Miami, Canada, Cincinnati, Shanghai, Paris): a positive 2–2 (50.0%) across 4 matches — winning above .500 at this level, week in week out, is a genuine sign of quality on hard.

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.

vs. Top 10 on hard: 1–7 (12.5%, 8 matches). Top 10 opponents have represented a clear ceiling on hard; addressing that deficit is the single biggest lever for improving the overall record here.

By format on hard — best-of-five: 7–13 (35.0%); best-of-three: 14–16 (46.7%). Markedly stronger in three-set formats; the win rate drops noticeably in five-setters, which has direct implications for Grand Slam performance on hard.

Best season: 2010 — 5–3 (62.5%) from 8 matches. The best single-season display to date — a useful reference point as the hard record continues to develop.