Spain's Marc Marquez won the opening MotoGP in Qatar on Sunday after a thrilling battle with Valentino Rossi.
The world champion, 21, held off the challenge from the veteran Italian, 35, despite racing with a broken leg.
Marquez pushed his Honda to the limit on the penultimate lap as he twice regained the lead after Valentino's Yamaha had edged in front.
"I enjoyed it. I did not think about the injury," said Marquez. "Last year he won, this year I won. I'm happy."
Marquez, who fractured his right fibula during a dirt-track training session in Lleida, near Barcelona last month, started in pole position and crossed the finish line 0.259secs ahead.
He added: "On the lap before the last we overtook each other two or three times which was so nice."
Dani Pedrosa (Honda) came in third while Britain's Cal Crutchlow (Ducati) and Scott Redding (Honda) finished sixth and seventh.
Spain's Esteve Rabat won the Moto2 race, beating Japan's Takaaki Nakagami with Finland's Mika Kallio finishing in third. Australia's Jack Miller won the Moto3 race.
Qatar MotoGP Results
1. Marc Marquez (Spain) Honda 42mins 40.561secs,
2. Valentino Rossi (Italy) Yamaha at 0.259secs,
3. Dani Pedrosa (Spain) Honda 3.370,
4. Aleix Espargaro (Spain) Yamaha 11.623,
5. Andrea Dovizioso (Italy) Ducati 12.159,
6. Cal Crutchlow (Britain) Ducati 28.526,
7. Scott Redding (Britain) Honda 32.593,
8. Nicky Hayden (US) Honda 32.628,
9. Colin Edwards (US) Yamaha 39.547,
10. Andrea Iannone (Italy) Ducati 43.360