Spaniard Jorge Lorenzo benefited from a spectacular crash by compatriot Dani Pedrosa to win the US Grand Prix on Sunday, a fourth victory in the last five races extending his world championship lead.
The 23-year-old Yamaha rider, who started on pole in bright sunshine at Laguna Seca, finished 3.517 seconds ahead of Ducati's Australian Casey Stoner, champion here in 2007.
Lorenzo twice punched his right fist forward in celebration after crossing the finish line, having extended his run of successive podiums to 10. He has finished no worse than second all season.
MotoGP champion Valentino Rossi outduelled fellow Italian Andrea Dovizioso to secure third place in only his second race back after breaking his right leg in practice for last month's Italian Grand Prix.
Pedrosa, who won last week's German Grand Prix, had powered ahead early in the 32-lap race before hitting a bump to crash out on the fifth turn of lap 12 to hand Lorenzo the overall lead.
"Dani was pushing so much but I knew if I kept pushing like him, maybe he make a mistake," a smiling Lorenzo told reporters after recording his sixth win of the season but his first at the US venue.
"I'm sorry he crashed but from then on it was very easy for me because I had a big gap over Casey. I'm so happy to win here at Laguna Seca. This is very special. I rode so well today, right on the limit."
With nine rounds of the championship to go, Lorenzo leads by a commanding 72 points with an overall tally of 210. Pedrosa has 138 and Dovizioso is third with 115 points.
Pedrosa, who began Sunday's race in fourth place on the grid, surged into the lead after the first turn before opening a 0.6-second advantage over the fast-starting Stoner after four laps.
Lorenzo snatched second place from Stoner on the sixth lap over the twisting, technically challenging circuit but he trailed Pedrosa by 1.104 seconds with 24 laps remaining.
Pedrosa, winner of last year's US Grand Prix and bidding for his third victory this season, then slid off his bike as he entered the left-hand fifth turn on lap 12 to gift Lorenzo the race lead which he never relinquished.
"It's very, very disappointing obviously but this can happen when you're trying everything to win," said Pedrosa, who triumphed at Laguna Seca 12 months ago after Lorenzo had been on pole.
"You have to push as much as you can and take risks -- and I really wanted to win this race. When I crashed, I was pushing hard to maintain my lead over Lorenzo and my rhythm was good."
Nine-times world champion Rossi, who needed the help of crutches to walk to his bike before the start of the race, was delighted with his first podium on his return to competition.
"It's great for me and it is very important to be back on the podium in such a short time," the 31-year-old said. "It was more difficult than we expected because this track is one of the toughest for the body."