Spaniard Jorge Lorenzo moved level with Italian Valentino Rossi at the top of the championship after winning the Czech MotoGP in Brno.
The 28-year-old Yamaha rider got a good start from pole position and won in a time of 42 minutes, 53.042 seconds.
Honda's Marc Marquez was 4.462 seconds behind to finish second with Rossi taking third to join his team-mate on 211 points in the standings.
It was a fifth win of the season for Lorenzo and his first since June.
"Luckily I had a little bit more pace than Marc and won this very important victory, because now I'm leading the championship with Valentino," said Lorenzo, the 2010 and 2012 MotoGP champion. "For Marc, it's now more difficult to recover."
Last season's champion Marquez is third in the championship on 159 points.
Lorenzo claimed his 38th overall MotoGP victory on the 22-lap, 5.4-km Brno circuit.
In the Moto3 race, Britain's Danny Kent, seeking to become the first Briton to win a world championship in any class since Barry Sheene in 1977, saw his lead cut to 45 points as he finished seventh. Italy's Niccolo Antonelli took the race win.
The Moto2 race was won by Frenchman Johann Zarco, who leads the championship standings by 79 points.
Czech Grand Prix results
1. Jorge Lorenzo (Spain) Yamaha 42mins 53.042secs
2 Marc Marquez (Spain) Honda 42:57.504
3. Valentino Rossi (Italy) Yamaha 43:03.439
4. Andrea Iannone (Italy) Ducati 43:06.113
5. Dani Pedrosa (Spain) Honda 43:08.692
6. Andrea Dovizioso (Italy) Ducati 43:08.766
7. Bradley Smith (Britain) Yamaha 43:14.863
8. Pol Espargaro (Spain) Yamaha 43:16.282
9. Aleix Espargaro (Spain) Suzuki 43:36.826
10. Danilo Petrucci (Italy) Ducati 43:38.303
MotoGP standings after race 11 of 18:
1= Valentino Rossi (Italy) Yamaha 211pts
1= Jorge Lorenzo (Spain) Yamaha 211,
3. Marc Marquez (Spa) Honda 159
4. Andrea Iannone (Ita) Ducati 142
5. Bradley Smith (Britain) Yamaha 106
6. Andrea Dovizioso (Ita) Ducati 104
7. Dani Pedrosa (Spain) Honda 91
8. Cal Crutchlow (Britain) Honda 74
9. Pol Espargaro (Spa) Yamaha 73
10. Danilo Petrucci (Ita) Ducati 63