Jan Siemerink has a competitive hard court record of 129–122 across 251 matches (51.4%). The record shows a player capable of competing here, though there is clear room to push the win rate higher. Claimed 2 titles on hard: Toulouse, Singapore.

At Grand Slam level (Australian Open & US Open): Jan Siemerink is 23–22 (51.1%) across 45 Grand Slam matches — below .500, though the elite draw depth at the Slams makes that a notoriously difficult barrier to crack.

ATP Masters 1000 on hard (Indian Wells, Miami, Canada, Cincinnati, Shanghai, Paris): a positive 26–22 (54.2%) across 48 matches — winning above .500 at this level, week in week out, is a genuine sign of quality on hard.

6 finals reached on hard — won 2, lost 4 (33% conversion) — capable of reaching finals consistently, with room to improve at the decisive moment. 11 semifinals. 16 quarterfinals.

vs. Top 10 on hard: 11–22 (33.3%, 33 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: 25–27 (48.1%); best-of-three: 104–95 (52.3%). Slightly stronger in three-set contests on hard, though the five-set record is still respectable.

Peak season: 1991 — 16–7 (69.6%) from 23 matches. That year captures the ceiling of what Jan Siemerink can do on hard when performing at their best and represents the standard to aim for.