MotoGP leader Marc Marquez has won his fourth straight Grand Prix of the Americas, the Spaniard again in a race of his own after a brief opening lap tussle with world champion Jorge Lorenzo.
With bitter rival Valentino Rossi one of several riders to crash, Marquez was far too good for Yamaha's Lorenzo, who finished 6.107 seconds behind his compatriot with Italian Andrea Iannone third on a Ducati.
The win was Marquez's second in a row, and 26th in MotoGP, and left the double world champion on 66 points after three races. Lorenzo moved up to second overall on 45, with Rossi remaining on 33.
Marquez was challenged only at the start, with Lorenzo leading into the first corner before running wide and doing the same at turn 11.
The Honda rider then had a controlled run to his 10th successive victory on US soil, which includes eight MotoGP races and two in Moto2, before raising four fingers in the air in triumph.
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"I think I did a really good race and I feel really great on this circuit," said Marquez.
"The race was not fun but we took 25 points which was the most important."
Rossi crashed out from sixth place on the third lap, with the Yamaha squirming away from him and into the gravel. It was the first time in 25 races that he had failed to finish in the top five.
Lorenzo fell behind Andrea Dovizioso in the battle for second place but re-took the Italian on lap five with the Ducati rider then taken out by Marquez's Spanish team mate Dani Pedrosa on the seventh lap.
Pedrosa lost control, with the bike sliding away from under him and straight into the Ducati.
British pair Cal Crutchlow and Bradley Smith both crashed at turn 11, with Smith's Yamaha just missing the LCR Honda rider.
Spaniard Maverick Vinales finished fourth for Suzuki after a thrilling battle with team mate Aleix Espargaro.
