F1 Championship leaders
Drivers’ Championship
| # | Grand Prix | Leader | Lead |
|---|---|---|---|
| 1 | USA | (BRA) Ayrton Senna | 4 |
| 2 | Brazil | (BRA) Ayrton Senna | 11 |
| 3 | San Marino | (BRA) Ayrton Senna | 20 |
| 4 | Monaco | (BRA) Ayrton Senna | 29 |
| 5 | Canada | (BRA) Ayrton Senna | 24 |
| 6 | Mexico | (BRA) Ayrton Senna | 24 |
| 7 | France | (BRA) Ayrton Senna | 25 |
| 8 | Britain | (BRA) Ayrton Senna | 18 |
| 9 | Germany | (BRA) Ayrton Senna | 8 |
| 10 | Hungary | (BRA) Ayrton Senna | 12 |
| 11 | Belgium | (BRA) Ayrton Senna | 22 |
| 12 | Italy | (BRA) Ayrton Senna | 18 |
| 13 | Portugal | (BRA) Ayrton Senna | 24 |
| 14 | Spain | (BRA) Ayrton Senna | 16 |
| 15 | Japan | (BRA) Ayrton Senna | 22 |
| 16 | Australia | (BRA) Ayrton Senna | 24 |
Notes
- The 1991 season was the seventh season, and first since 1969, in which the Drivers’ Championship was led from start to finish by the same driver.
- Ayrton Senna was the sixth driver and the first Brazilian driver to achieve this feat.
- First time as championship leader
- No driver led the championship for the first time in 1991
- Last time as championship leader
- No driver led the championship for the last time in 1991
- Last time as championship leader until…
- 1993 for Ayrton Senna
- Last time as championship leader by a…
- Brazilian driver until 1993
Constructors’ Championship
| # | Grand Prix | Leader | Lead |
|---|---|---|---|
| 1 | USA | McLaren-Honda | 4 |
| 2 | Brazil | McLaren-Honda | 14 |
| 3 | San Marino | McLaren-Honda | 30 |
| 4 | Monaco | McLaren-Honda | 34 |
| 5 | Canada | McLaren-Honda | 31 |
| 6 | Mexico | McLaren-Honda | 21 |
| 7 | France | McLaren-Honda | 13 |
| 8 | Britain | McLaren-Honda | 12 |
| 9 | Germany | Williams-Renault | 1 |
| 10 | Hungary | McLaren-Honda | 2 |
| 11 | Belgium | McLaren-Honda | 16 |
| 12 | Italy | McLaren-Honda | 15 |
| 13 | Portugal | McLaren-Honda | 11 |
| 14 | Spain | Williams-Renault | 1 |
| 15 | Japan | McLaren-Honda | 11 |
| 16 | Australia | McLaren-Honda | 14 |
- First time as championship leader
- No constructor led the championship for the first time in 1991
- Last time as championship leader
- No constructor led the championship for the last time in 1991