Kết quả phiên chạy FP4 chặng đua MotoGP San Marino 2021:
| Stt | Tay đua | Xe | Km/h | Thời gian | Kh/cách |
| 1 | Fabio QUARTARARO | Yamaha | 289.5 | 1’32.197 | |
| 2 | Alex RINS | Suzuki | 294.2 | 1’32.287 | 0.090 / 0.090 |
| 3 | Francesco BAGNAIA | Ducati | 295.8 | 1’32.333 | 0.136 / 0.046 |
| 4 | Johann ZARCO | Ducati | 298.3 | 1’32.505 | 0.308 / 0.172 |
| 5 | Joan MIR | Suzuki | 288.7 | 1’32.578 | 0.381 / 0.073 |
| 6 | Enea BASTIANINI | Ducati | 295.8 | 1’32.635 | 0.438 / 0.057 |
| 7 | Takaaki NAKAGAMI | Honda | 292.6 | 1’32.681 | 0.484 / 0.046 |
| 8 | Marc MARQUEZ | Honda | 295.8 | 1’32.697 | 0.500 / 0.016 |
| 9 | Aleix ESPARGARO | Aprilia | 295.8 | 1’32.724 | 0.527 / 0.027 |
| 10 | Jack MILLER | Ducati | 294.2 | 1’32.768 | 0.571 / 0.044 |
| 11 | Michele PIRRO | Ducati | 292.6 | 1’32.772 | 0.575 / 0.004 |
| 12 | Maverick VIÑALES | Aprilia | 295.0 | 1’32.926 | 0.729 / 0.154 |
| 13 | Jorge MARTIN | Ducati | 293.4 | 1’32.954 | 0.757 / 0.028 |
| 14 | Pol ESPARGARO | Honda | 294.2 | 1’32.958 | 0.761 / 0.004 |
| 15 | Alex MARQUEZ | Honda | 295.8 | 1’33.028 | 0.831 / 0.070 |
| 16 | Brad BINDER | KTM | 292.6 | 1’33.044 | 0.847 / 0.016 |
| 17 | Valentino ROSSI | Yamaha | 290.3 | 1’33.086 | 0.889 / 0.042 |
| 18 | Iker LECUONA | KTM | 291.1 | 1’33.228 | 1.031 / 0.142 |
| 19 | Miguel OLIVEIRA | KTM | 295.0 | 1’33.260 | 1.063 / 0.032 |
| 20 | Luca MARINI | Ducati | 295.0 | 1’33.266 | 1.069 / 0.006 |
| 21 | Franco MORBIDELLI | Yamaha | 289.5 | 1’33.280 | 1.083 / 0.014 |
| 22 | Stefan BRADL | Honda | 295.8 | 1’33.305 | 1.108 / 0.025 |
| 23 | Danilo PETRUCCI | KTM | 291.1 | 1’33.551 | 1.354 / 0.246 |
| 24 | Andrea DOVIZIOSO | Yamaha | 286.4 | 1’33.605 | 1.408 / 0.054 |
Nguồn: Tổng hợp
