Who are the youngest Grand Prix premier class winners?

Top 10 youngest premier class Grand Prix winners:
1. Marc Marquez – 20 years, 63 days (Circuit of the Americas 2013)
2. Freddie Spencer – 20 years, 196 days (Spa-Francorchamps 1982)
3. Norifumi Abe – 20 years, 227 days (Suzuka 1996)
4. Dani Pedrosa – 20 years, 227 days (Shanghai International Circuit 2006)
5. Randy Mamola – 20 years, 239 days (Spa-Francorchamps 1980)
6. Jorge Lorenzo – 20 years, 345 days (Circuito do Estoril 2008)
7. Mike Hailwood – 21 years, 75 days (Isle of Man 1975)
8. Fabio Quartararo – 21 years, 90 days (Circuito de Jerez-Angel Nieto 2020)
9. Valentino Rossi – 21 years, 144 days (Donington Park 2000)
10. Casey Stoner – 21 years, 145 days (Losail International Circuit 2007)