Head to head
1
Hard
0
1
Clay
1
Nicholas Kalogeropoulos's wins on the left · John Alexander's on the right · bar lengths share one scale
All meetings (3)
| 1971 | Johannesburg | Hard | R32 | Nicholas Kalogeropoulos | 6-7 6-7 6-2 6-1 6-3 |
| 1969 | St. Petersburg | Clay | R32 | Nicholas Kalogeropoulos | 6-3 7-5 |
| 1968 | Palermo | Clay | R16 | John Alexander | 6-3 6-4 |
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.