Head to head
Rivalry summary
Alex O'Brien and Marcos Ondruska met 2 times on the ATP tour between 1997 and 2000. Alex O'Brien leads the head-to-head 2–0 against Marcos Ondruska. By surface, O'Brien leads 2–0 on hard.
2
Hard
0
Alex O'Brien's wins on the left · Marcos Ondruska's on the right · bar lengths share one scale
All meetings (2)
| 2000 | Washington | Hard | R64 | Alex O'Brien | 6-7(3) 6-4 6-3 |
| 1997 | Canada Masters | Hard | R32 | Alex O'Brien | 6-4 7-6(7) |
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.