"My strategy was just start, push and that's it", said Marquez, who shrugged off boos from the crowd reacting to a champion whose on-track clashes with rivals have been a talking point of the season. Iannone stood on the last step of the podium and it was a special performance for the Italian rider as it was his first podium finish for Suzuki after joining them previous year.
Meanwhile, Vinales went past Iannone, but he managed to keep Rossi behind him despite pressure from the Yamaha rider.
Vinales was confident he could challenge Marquez in the race even before the penalty was announced. A brief contest from Andrea Iannone on the improving Suzuki was as close as anyone would come to challenging the Repsol Honda man, who pulled away by nearly a second a lap in the opening laps before managing his lead in the second half of the race. Marquez has won the Texas race five years in a row and Sunday will be the first time he doesn't start in pole position. Today I think was the maximum we could do.
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After the controversy of Argentina, where Marquez was penalised for several riding infringements, including knocking off Valentino Rossi, the world champion was back in front of race officials on Saturday after he blocked Maverick Vinales' flying lap during qualifying. With 12 laps remaining in the race, Crutchlow, who was leading the championship standing after the opening two rounds crashed out in an attempt to safeguard his sixth position.
Dani Pedrosa gritted his teeth to claim seventh despite his wrist injury, while Avintia's Tito Rabat held Ducati stablemate Jack Miller and Aprilia's Aleix Espargaro to secure eighth, while Jorge Lorenzo was cast a distant 11th. Danilo Petrucci, Pol Espargaro, Taka Nakagami and Alvaro Bautista compled the top 15. It was mostly status quo for the rest of the race apart from a few fallers including championship leader Cal Crutchlow.
Andrea Iannone passed slow-starting pole-sitter Vinales to lead going into Turn 1, but Marquez also got off to a flyer and was in front after overtaking at the end of the back straight.
Bradley Smith was the first British rider home in a disappointing 16 place for KTM, ahead of compatriot Scott Redding.