7‑Nov‑1988 | Buenos Aires | Clay | R32 | 258 | 192 | Roberto Arguello [ARG] d. Yunis | 6-4 6-2 | | | | | | | | | |
19‑Sep‑1988 | Bari | Clay | R32 | 229 | 47 | (4)Marcelo Filippini [URU] d. Yunis | 6-2 6-3 | | | | | | | | | |
8‑Aug‑1988 | Prague | Clay | R32 | 174 | 48 | (4)Tomas Smid [CZE] d. Yunis | 3-6 6-1 6-4 | | | | | | | | | |
25‑Jul‑1988 | Hilversum | Clay | R16 | 177 | 54 | (6)Alberto Mancini [ARG] d. Yunis | 6-4 6-2 | | | | | | | | | |
25‑Jul‑1988 | Hilversum | Clay | R32 | 177 | 127 | Yunis d. Hans Schwaier [GER] | 6-4 6-4 | | | | | | | | | |
11‑Jul‑1988 | Bastad | Clay | R64 | 151 | 137 | Jean Philippe Fleurian [FRA] d. Yunis | 6-3 6-0 | | | | | | | | | |
13‑Jun‑1988 | Athens | Clay | R32 | 112 | 92 | (2)Guillermo Vilas [ARG] d. Yunis | 6-2 7-6 | | | | | | | | | |
6‑Jun‑1988 | Bologna | Clay | R16 | 106 | 67 | (5)Alberto Mancini [ARG] d. Yunis | 6-1 6-1 | | | | | | | | | |
6‑Jun‑1988 | Bologna | Clay | R32 | 106 | 251 | Yunis d. (Q)Roberto Azar [ARG] | 6-3 3-6 6-1 | | | | | | | | | |
23‑May‑1988 | Roland Garros | Clay | R64 | 96 | 3 | (3)Mats Wilander [SWE] d. (Q)Yunis | 6-2 6-3 6-1 | | | | | | | | | |
23‑May‑1988 | Roland Garros | Clay | R128 | 96 | 266 | (Q)Yunis d. (Q)Eduardo Osta [ESP] | 6-2 6-4 2-6 6-3 | | | | | | | | | |
2‑May‑1988 | Munich | Clay | R32 | 115 | 19 | (2)Emilio Sanchez [ESP] d. Yunis | 6-0 6-1 | | | | | | | | | |
2‑May‑1988 | Munich | Clay | R64 | 115 | 109 | Yunis d. Cassio Motta [BRA] | 6-3 6-4 | | | | | | | | | |
25‑Apr‑1988 | Hamburg | Clay | R16 | 141 | 29 | (7)Guillermo Perez Roldan [ARG] d. (Q)Yunis | 7-6 6-1 | | | | | | | | | |
25‑Apr‑1988 | Hamburg | Clay | R32 | 141 | 36 | (Q)Yunis d. (10)Eduardo Bengoechea [ARG] | 6-4 6-2 | | | | | | | | | |
25‑Apr‑1988 | Hamburg | Clay | R64 | 141 | 119 | (Q)Yunis d. Yahiya Doumbia [SEN] | 6-2 7-6 | | | | | | | | | |
11‑Apr‑1988 | Madrid | Clay | R32 | 152 | 97 | Alberto Mancini [ARG] d. Yunis | 3-6 6-4 6-1 | | | | | | | | | |