Marc Marquez extended his lead at the top of the MotoGP World Championship by beating Stefan Bradl at Laguna Seca.
Marquez, 20, had never raced at the California circuit before but produced a superb ride to stretch his advantage over his Repsol Honda team-mate Dani Pedrosa to 16 points.
Valentino Rossi was third with Alvaro Bautista fourth and the injured Pedrosa and Jorge Lorenzo fifth and sixth.
Britain's Cal Crutchlow had his worst finish of the season in seventh place.
after missing last weekend's German Grand Prix with collarbone injuries, and despite neither being fully fit they were able to remain in the title race by taking top-six finishes.
But rookie Marquez took full advantage of his rivals' troubles by seeing off a determined ride from pole-sitter Bradl - who took his first ever podium finish - to win for the third time in MotoGP and enter the mid-season break on top.
There was a minute's silence before the race as MotoGP marked the death of Italian rider Andrea Antonelli - who was killed in an accident during the World Supersport race in Moscow earlier on Sunday.
Bradl and Rossi then made cracking starts to move ahead before Marquez passed Rossi to take second place with a daring pass.
Marquez lunged around the outside of Rossi as the riders tipped into the corkscrew - Laguna Seca's trademark corner - with both riders running wide across the sand.
It was reminiscent of Rossi's own move on Casey Stoner at the same corner in 2008 and a further sign of the Spaniard's prodigious talent.
Marquez then stalked Bradl before passing the German with 13 laps to go.
Rossi told BBC Sport: "It looks like Marc made my own overtake but I have the trademark! He owes me some money!"
Marquez said: "I had been watching videos of Valentino from 2008 and I thought it was impossible to repeat that move.
"But when I passed him I had to go wide and it was exactly the same.
"I am so happy to win, I thought I would struggle here but I have taken 25 points and now we can enjoy the break."
Crutchlow made a bad start from fifth on the grid and could make no impression on the injured duo of Lorenzo and Pedrosa.
There is now a month-long break in the series, with the next round taking place at Indianapolis on 18 August.
United States Grand Prix results
1. Marc Marquez (Spa) Repsol Honda 44'00.695
2. Stefan Bradl (Ger) LCR Honda 44'02.993
3. Valentino Rossi (Ita) Yamaha 44'05.193
4. Alvaro Bautista (Spa) Gresini Honda 44'05.252
5. Dani Pedrosa (Spa) Repsol Honda 44'09.952
6. Jorge Lorenzo (Spa) Yamaha 44'13.665
7. Cal Crutchlow (GB) Tech 3 Yamaha 44'15.999
8. Nicky Hayden (US) Ducati 44'34.658
9. Andrea Dovizioso (Ita) Ducati 44'34.824
10. Hector Barbera (Spa) FTR 45'03.064