Head to head
2
Hard
1
Jan Siemerink's wins on the left · Alex O'Brien's on the right · bar lengths share one scale
All meetings (3)
| 1999 | Miami Masters | Hard | R64 | Jan Siemerink | 7-5 7-5 |
| 1996 | New Haven | Hard | F | Alex O'Brien | 7-6(6) 6-4 |
| 1995 | Auckland | Hard | R16 | Jan Siemerink | 7-5 6-3 |
Methodology
Head-to-head totals and surface splits exclude walkovers (no match was played), which follows ATP convention — walkover meetings still appear in the match list. The momentum chart plots the running lead across all counted meetings, oldest to newest.