| 1991-11-04 | Sao Paulo | Hard | R32 | 29 |  Javier Sanchez (4) | 107 |  Luiz Mattar | 6-7(11) 7-6(4) 1-2 DEF | H2H | 3 | 140 | 7 | 1 | 63.8% | 71.6% | 52.4% | 8/9 |
| 1991-10-28 | Buzios | Hard | R32 | 36 |  Paul Haarhuis (5) | 96 | Luiz Mattar | 7-6(0) 6-3 | H2H | 3 | 95 | 8 | 2 | 61.4% | 83.7% | 48.1% | 4/5 |
| 1991-10-21 | Guaruja | Hard | R16 | 212 | Francisco Roig | 92 | Luiz Mattar | 6-2 5-7 6-4 | H2H | 3 | 140 | 4 | 0 | 63.8% | 60.0% | 50.0% | 8/13 |
| 1991-10-21 | Guaruja | Hard | R32 | 92 | Luiz Mattar | 35 |  Thomas Muster (1) | 6-3 6-2 | H2H | 3 | 88 | 8 | 3 | 57.1% | 75.0% | 50.0% | 7/8 |
| 1991-09-20 | Davis Cup WG PO: BRA vs IND | Clay | RR | 74 | Luiz Mattar | 157 |  Ramesh Krishnan | 5-7 6-3 6-3 6-4 | H2H | 5 | - | - | - | - | - | - | - |
| 1991-09-20 | Davis Cup WG PO: BRA vs IND | Clay | RR | 74 | Luiz Mattar | 330 | Leander Paes | 6-4 6-3 6-2 | H2H | 5 | - | - | - | - | - | - | - |
| 1991-09-09 | Geneva | Clay | R32 | 23 |  Alberto Mancini (5) | 73 | Luiz Mattar | 6-3 7-6(5) | H2H | 3 | 117 | 7 | 0 | 66.7% | 80.0% | 55.0% | 3/4 |
| 1991-08-26 | US Open | Hard | R32 | 16 |  Goran Ivanisevic (12) | 68 | Luiz Mattar | 6-3 6-2 6-2 | H2H | 5 | 86 | 18 | 1 | 55.9% | 86.8% | 66.7% | 0/0 |
| 1991-08-26 | US Open | Hard | R64 | 68 | Luiz Mattar | 34 |  Cristiano Caratti | 3-6 6-3 6-0 7-6(3) | H2H | 5 | 175 | 10 | 0 | 67.2% | 74.4% | 57.9% | 8/10 |
| 1991-08-26 | US Open | Hard | R128 | 68 | Luiz Mattar | 298 |  Rick Leach (WC) | 6-3 3-6 7-6(10) 6-2 | H2H | 5 | 167 | 5 | 2 | 64.0% | 72.6% | 65.9% | 0/2 |
