Marc Marquez put the seal on his record-breaking weekend at Austin's Circuit of The Americas by becoming the youngest winner in the history of MotoGP.
The Spaniard was pushed all the way by his works Honda teammate Dani Pedrosa, with the pair rarely separated by more than half a second.
Three laps from the finish, however, Pedrosa suddenly dropped more than one second, allowing Marquez precious breathing space at the front.He duly converted that into a first premier class victory at only his second attempt, and at the age of 20 years, two months and four days. He is now the joint points leader, level with last year's champion Jorge Lorenzo.
Pedrosa had moved to the front as the field made its way through Turn 1 for the first time, and continued to lead until Marquez slipped up the inside at Turn 7 after half-distance. He initially stuck with his younger stablemate, even coming close to running into the back of him under braking, but ultimately had to settle for second.
Yamaha's Lorenzo was only able to keep up with the works Hondas for the first five laps before slowing dropping away. His deficit stabilized at around 3sec, however, a gap he preserved until the finish.
Yamaha's Tech 3 satellite rider Cal Crutchlow claimed fourth, three seconds down the road. The Briton had been stuck behind LCR Honda's Stefan Bradl in the early stages, but eventually picked his way past on lap nine and was largely able to match the lead trio's pace thereafter.
Bradl was fifth ahead of a relatively lonely ride from Valentino Rossi on the second works Yamaha.
Rossi had earlier been battling with Ducati's Andrea Dovizioso and the final satellite Honda of Alvaro Bautista. While the Italian was able to pull clear, Dovizioso and Bautista remained locked in battle right up until the flag. The Ducati eventually prevailed by just under half a second.
Circuit of The Americas reported that it attracted more than 131,000 fans for the first appearance of MotoGP at the USGP F1 venue.
Results - 21 laps:
Pos Rider Team/Bike Time/Gap
1. Marc Marquez Honda 43m42.123s
2. Dani Pedrosa Honda + 1.534s
3. Jorge Lorenzo Yamaha + 3.381s
4. Cal Crutchlow Tech 3 Yamaha + 6.616s
5. Stefan Bradl LCR Honda + 12.674s
6. Valentino Rossi Yamaha + 16.615s
7. Andrea Dovizioso Ducati + 22.374s
8. Alvaro Bautista Gresini Honda + 22.854s
9. Nicky Hayden Ducati + 33.773s
10. Andrea Iannone Pramac Ducati + 42.112s
11. Aleix Espargaro Aspar Aprilia + 48.837s
12. Bradley Smith Tech 3 Yamaha + 50.705s
13. Ben Spies Pramac Ducati + 1m14.132s
14. Randy de Puniet Aspar Aprilia + 1m15.651s
15. Yonny Hernandez PBM Aprilia + 1m19.591s
16. Michael Laverty PBM-Aprilia + 1m34.391s
17. Hiroshi Aoyama Avintia FTR-Kawasaki + 1m39.823s
18. Hector Barbera Avintia FTR-Kawasaki + 1m39.952s
19. Claudio Corti Forward FTR-Kawasaki + 1m46.773s
20. Bryan Staring Gresini FTR-Honda + 1m48.084s
21. Blake Young Attack APR-Kawasaki + 1 lap
Danilo Petrucci Ioda-Suter-BMW 13 laps
Lukas Pesek Ioda-Suter-BMW 13 laps
Colin Edwards Forward FTR-Kawasaki 11 laps