Six-time premier-class champion Marquez did not finish a single grand prix in 2020 due to injury and has struggled at times with his fitness again this year, unable to play a part in the title race.
But the Repsol Honda great provided a reminder of his talent with a straightforward second win of the season in Texas on Sunday.
Marquez had won on 10 of his 11 previous appearances in the United States, only failing at the previous GP of the Americas in 2019 as he retired.
He started from third but led from the first corner, ducking up the inside and never looking like relinquishing his advantage.
Marquez maintained a steady pace initially, but having held his own looked to kick clear and was comfortable all the way to prompt celebrations in his garage.
Crucially in terms of the title picture, Quartararo followed Marquez over the line, his second consecutive second-placed finish enough to stretch his season lead.
Francesco Bagnaia, Quartararo's nearest rival, started from pole for a third race running but could not follow up back-to-back victories with a third.
He was forced to settle for third and now trails by 52 points with only three grands prix remaining.
- Marc Marquez (Repsol Honda)
- Fabio Quartararo (Monster Energy Yamaha) +4.679s
- Francesco Bagnaia (Ducati) +8.457s
- Alex Rins (Suzuki Ecstar) +11.098s
- Jorge Martin (Pramac Racing) +11.752s
- Enea Bastianini (Avintia) +13.269s
- Jack Miller (Ducati) +14.722s
- Joan Mir (Suzuki Ecstar) +13.406s
- Brad Binder (Red Bull KTM) +15.832s
- Pol Espargaro (Repsol Honda) +20.265s
- Fabio Quartararo (Monster Energy Yamaha) 254
- Francesco Bagnaia (Ducati) 202
- Joan Mir (Suzuki Ecstar) 175
- Jack Miller (Ducati) 149
- Johann Zarco (Pramac Racing) 141
- Ducati 351
- Monster Energy Yamaha 349
- Suzuki Ecstar 256
- Pramac Racing 227
- Red Bull KTM 223