Honda rider Marquez made the ideal launch from pole position to produce a break at the beginning, opening a one-second lead within a similarly fast-starting Valentino Rossi about the first tour.
The reigning champion then started setting a fearsome pace that none of his rivals could match, extending his advantage into three minutes following three laps.
After 10 of 25 laps, he Marquez had been a whole seven seconds in the clear, along with his guide peaked at more than 12 seconds at the latter stages until he finally crossed the line with 9.8s in his pocket to get his next win in Termas de Rio Hondo.
Beneath , the struggle for second has been fought chiefly between Rossi and Dovizioso, with Yamaha rider Rossi recovering from conducting wide at Turn 5 on lap seven to retake the area the following tour.
Dovizioso found a method back by his countryman on lap 13, but wasn’t able to flee Rossi, who dived straight back beyond the Italian Turn 7 to the final lap to come home next.
A frenetic scrap for fourth place went the way of Jack Miller, after the Pramac Ducati rider made overdue passes on Alex Rins – up from 16th on the grid – and the second works Ducati of Danilo Petrucci.
Rossi’s team mate Maverick Vinales made a bad start from second on the grid to drop to fourth on the opening lap, then slumped to eighth on lap .
The Spaniard looked set to take seventh place before being taken from the Petronas SRT Yamaha of both Franco Morbidelli in the previous lap at Flip 7.
This accident promoted Takaaki Nakagami (LCR Honda) to ahead of Fabio Quartararo (Petronas), Aleix Espargaro (Aprilia) and Pol Espargaro (KTM).
Underneath Tech 3 KTM rookie Miguel Oliveira, Jorge Lorenzo brought home the second Repsol Honda at 12th, the exact same position he qualified, recovering some places after dropping from those points early on.
Cal Crutchlow (LCR Honda) blew a strong chance to participate in the podium fight with a jump-start, earning himself a ride-through penalty that left him down in 13th.
Johann Zarco finished 15 th for the next race in a row over the second of the works KTMs, whereas Andrea Iannone (Aprilia) was among the finishers at 17th.
Both Avintia Ducatis of both Tito Rabat and Karel Abraham crashed outside, whereas Suzuki’s Joan Mir retired in the pits after a lurid grass-tracking time late in the race.