The Repsol Honda rider has won every race of the 2014 season and negotiated a wet track to win the Netherlands MotoGP after another excellent performance.
Marquez completed his 26 laps in a time of 43 minutes and 29.954 seconds to extend his lead at the top of the standings to 72 points.
The Spaniard eventually got the better of Ducati's Andrea Dovizioso (+6.714secs) in a fascinating duel, while the former's team-mate, Dani Pedrosa (+10.791secs) was third.
NGM Forward Racing's Aleix Espargaro (+19.199secs) started from pole, but could not manage a podium finish, while Movistar Yamaha's Valentino Rossi (+25.814secs) ended well for fifth.
But it was Marquez's day, as he became the first rider since Giacomo Agostini in 1971 to win the first eight premier-class races of the year.
Pedrosa and Rossi are now locked in second in the standings, on 128 points, while Dovizioso climbed to fourth.
After the start was delayed due to persistent rain, riders knew they would be in for a tough day.
The officials gave the field two extra laps to decide whether to start on slick or wet tyres, but they all quickly changed to slick-shod bikes after Marquez and Dovizioso did so.
Marquez stormed past Espargaro from the start, but Dovizioso offered serious competition, as they swapped positions in the lead four times on the opening lap.
The race winner slid off the track on cold slicks, though, allowing Dovizioso to reclaim the lead.
But after putting significant pressure on the Ducati man, Marquez moved in front with 10 laps to go and he never looked back to claim another win, celebrating by making a swimming gesture as he crossed the finish line.
Pedrosa was too good for Espargaro, while Rossi made a late charge to feature in the top five.
Andrea Iannone (Pramac Racing), Alvaro Bautista (GO&FUN Honda Gresini), Bradley Smith (Monster Yamaha Tech3), Cal Crutchlow (Ducati Team) and Stefan Bradl (LCR Honda MotoGP) rounded out the top 10.
It was a terrible day for two-time world champion Jorge Lorenzo, though.
The Yamaha rider, who now sits fifth in the race for the world title, switched to slick tyres too late and could not recover, eventually finishing 13th.