Marc Marquez cruised to a seventh win at the Circuit of the Americas as Fabio Quartararo extended his points lead by finishing as runner-up.
Marquez made a lightning start to immediately pass fellow front-row men Francesco Bagnaia and Quartararo, the latter following the Honda man through to second as the field navigated Turn 1 for the first time.
The six-time premier class champion held a slender lead over the Yamaha racer across the opening stages of the contest, though as mid-distance approached he turned up the wick as he began to lap around half-a-second per lap quicker than his pursuers, Marquez extending his lead up to 3.5 seconds in just a few tours.
Quartararo found himself unable to do much about Marquez across the remaining half of the race and instead focussed on trying to maintain second ahead of Pramac’s Jorge Martin, though the rookie started to struggle with tyre wear in the closing laps-thus allowing the Frenchman off the hook.
Marquez ultimately took the chequered flag to secure his second win of the season 4.6 seconds clear of Quartararo, extending his series lead by four points over Bagnaia who managed to grab the final rostrum spot after Martin received a long-lap punishment.
The 2018 Moto3 world champion ran wide at the esses while trying to hold off the closing Italian, earning him a long-lap penalty due to not forgoing enough time after running through the run-off area on the inside of the corner.
Bagnaia managed to find a way through anyway prior to Martin taking his long-lap to take third, with Suzuki’s Alex Rins taking profit from Martin’s loss of time to come home fourth ahead of the rookie.
Enea Bastianini staged a late charge similar to his San Marino comeback to snatch sixth after passing both Joan Mir and a fading Jack Miller just moments before the end, reigning MotoGP world champion Mir therefore seventh and Miller a disappointing eighth.
The pair would be swapped post-race though after the race stewards took a dim view over the way Mir muscled past Miller on the last lap, the latter thus being classified seventh ahead of Mir in eighth.
The Aussie looked good to fight for victory after selecting the hard compound rear tyre that in theory would give him an advantage in the latter stages, though after reaching fifth started to plateau-eventually forcing him to wave through team-mate Bagnaia as he fell away.
Brad Binder was ninth for KTM while Pol Espargaro completed the top ten on the second factory Honda machine.
Andrea Dovizioso meanwhile scored his first points of the year in 13th after out-racing fellow Petronas SRT Yamaha man Valentino Rossi, who ended up 15th.
Takaaki Nakagami finished 17th ahead of Danilo Petrucci and Franco Morbidelli despite crashing from sixth at Turn 12 on the second circulation, the LCR ace lapping as fast as Marquez in the closing laps in what was yet another missed opportunity for the Japanese rider.
Johann Zarco and Aleix Espargaro were the only men that failed to reach the chequered flag after both crashing out, the former going down at Turn 1 from ninth only five laps in while the latter slid out at Turn 13 to cap off a messy weekend for the Aprilia man.
Quartararo now holds a 52 point advantage over Bagnaia with three races remaining, the Ducati pilot now the only one who can stop his march to the title as Mir, Miller and Zarco all dropped more than 75 markers adrift.