17‑Jun‑1972 | Bristol | Grass | R16 | | | Clark Graebner [USA] d. Koch | 6-1 4-6 7-5 | | | | | | | | | |
22‑May‑1972 | Roland Garros | Clay | R64 | | | (11)Clark Graebner [USA] d. Koch | 6-2 6-0 6-2 | | | | | | | | | |
1‑Mar‑1971 | Macon | Hard | QF | | | Clark Graebner [USA] d. Koch | 6-2 3-6 7-5 | | | | | | | | | |
28‑Sep‑1970 | Berkeley | Hard | R16 | | | (15)Koch d. (5)Clark Graebner [USA] | 6-3 6-1 | | | | | | | | | |
2‑Mar‑1970 | Hampton | Carpet | SF | | | Koch d. Clark Graebner [USA] | 4-6 10-8 4-6 6-3 6-3 | | | | | | | | | |
28‑Jan‑1970 | Omaha | Hard | QF | | | Koch d. Clark Graebner [USA] | 9-7 6-1 | | | | | | | | | |
31‑Jan‑1969 | Richmond | Carpet | F | | | Clark Graebner [USA] d. Koch | 6-3 10-12 9-7 | | | | | | | | | |
8‑Jan‑1968 | Bloemfontein | Hard | QF | | | Clark Graebner [USA] d. Koch | 6-8 6-2 6-1 | | | | | | | | | |