Marc Marquez became the youngest ever race winner in MotoGP as the inexperienced Spaniard took the chequered flag at today's Grand Prix of the Americas in Austin.

The 20-year-old yesterday became the youngest pole-sitter in the history of the sport and completed the set today following an accomplished ride on just his second outing in motorcycling's premier racing series.

The only blot for Marquez was his failure to hold his lead off the start, but after passing team-mate Dani Pedrosa with nine laps remaining the final result rarely looked in doubt.

Pedrosa, 27, was graceful in defeat as he came home in second, while Yamaha's Jorge Lorenzo held off a spirited display by Britain's Cal Crutchlow to take the final podium place.

"It's unbeliveable. My first victory in MotoSP is a dream come true, especially as the race was quite hard," Marquez, the reigning Moto2 champion, told BBC Sport.

"I chose the best tyre [combination] but I want to say thanks to everyone who helped me to this moment."

The ease with which Marquez has transitioned to the premier class has raised eyebrows up and down the paddock, with today's performance emphatically destroying the theory that his third place at the opening round in Qatar was a flash in the pan.

Marquez belied his tender years and lack of experience as he refused to rush to re-take Pedrosa after falling behind his compatriot at the start of the race, instead biding his time to re-take the lead with an assured move after half-distance.

Pedrosa admitted he struggled with a muscular problem in his arm later in the race, which he attributed to the heavy breaking zones around the Texan track, but felt a mistake a few laps from home ultimately cost him a shot at the victory.

"I was very happy with how I was working the bike, but in the chicane section I started to be slower and I started to lose strength in my left arm, so when Marc passed me I was losing a lot of ground in the first section," said Pedrosa.

"Three laps from the end I did a bad lap time, maybe one and a half seconds slower, and that's where I lost the race."

Behind Qatar winner Lorenzo and the Yamaha of Crutclow, Stefan Bradl was fifth for LCR Honda, while Lorenzo's team-mate Valentino Rossi came home in sixth place as the Italian failed to replicate the pace that saw him finish second at the season-opener.