SILVERSTONE, England -- Jorge Lorenzo extended his lead in the MotoGP standings by securing a convincing victory in the British Grand Prix at Silverstone on Sunday, a third straight win in a dominant season for the Yamaha rider.

Starting fourth on the grid, Lorenzo moved through the field to win his fourth race in six this season by more than 3 seconds from Australia's Casey Stoner.

The Spaniard now has a 25-point lead in the overall standings over Stoner, who finished narrowly ahead of Honda teammate Dani Pedrosa.

"This season is just perfect," said Lorenzo, who this week signed a new two-year contract with Yamaha.

Lorenzo dropped to sixth place after a poor start but went in front for the first time at the halfway point. The lead changed hands between him and Stoner five times in half a lap before Lorenzo pulled away decisively.

"Fighting with Casey, I enjoyed it a lot," said Lorenzo, who has 140 points. Stoner has 115 and Pedrosa 101.

Alvaro Bautista, who started on pole position, was fourth while Britain's Cal Crutchlow finished sixth despite starting from the back of the grid following a crash before qualifying on Saturday. Crutchlow sprained his left ankle in the crash and spent time in a hospital.

"It was a long day yesterday -- they told me I wasn't allowed to ride at the hospital," he said. "(It's) a shame I wasn't at the front of the grid because I would have been on the podium."