Head to head
2
Clay
0
1
Grass
1
Clark Graebner's wins on the left · Robert McKinley's on the right · bar lengths share one scale
All meetings (4)
| 1972 | South Orange | Grass | R32 | Robert McKinley | 6-3 7-6 |
| 1971 | Haverford | Grass | R16 | Clark Graebner | 6-4 7-5 |
| 1970 | Cincinnati | Clay | R64 | Clark Graebner | 7-5 6-4 |
| 1969 | Houston | Clay | QF | Clark Graebner | 6-4 6-2 |
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.