Honda rider Marquez now has a healthy advantage of 36 points at the head of the table following a victory that looked in little doubt after his two main rivals dropped out of the running.

Marquez had slumped as low as sixth at the start of a tough opening lap, as Jorge Lorenzo vaulted from sixth on the grid into an early lead over poleman Zarco and Dovizioso.

By the end of the second lap, Marquez had recovered to fourth, joining a four-rider lead group.

Dovizioso picked off home favourite Zarco for second place at the downhill La Chapelle right-hander on the third lap, and had just passed Lorenzo to take the lead at the start of the fifth lap.

But as the lead group plunged into La Chapelle once more, Dovizioso lost the front end of his factory Ducati and slid into the gravel, forcing his second retirement in as many races.

Three laps later, while defending second from Marquez, Zarco suffered a similar fate to Dovizioso as he fell at the Garage Vert double right-hander, ending his hopes of a maiden MotoGP win.

That left Lorenzo with a narrow lead over Marquez, but it was clear that Marquez had superior pace to the sole remaining works Ducati man, and the inevitable pass came at La Chapelle on the 10th lap.

Danilo Petrucci, promoted to third by the demise of Dovizioso and Zarco, managed to follow Marquez past Lorenzo on the next lap at the Musee left-hander, but couldn't mount a challenge for the lead.

Marquez was able to reel off the remaining laps and claim victory by a final margin of 2.310 seconds.

After being passed by Petrucci's Pramac machine, Lorenzo couldn't stave off Yamaha's Valentino Rossi, who moved ahead at La Chapelle to claim his first podium finish since the Qatar opener in third place.

Lorenzo then surrendered further places to the second Pramac Ducati of Jack Miller and Dani Pedrosa on the second works Honda, ending up sixth, 10 seconds down on Marquez.

Maverick Vinales had been running as low as 13th in the early laps on his works Yamaha but managed to recover to seventh, a further 13 seconds back, while Cal Crutchlow (LCR Honda) passed Aleix Espargaro (Aprilia) on the last lap to grab eighth after his huge qualifying crash left him in doubt for the race.

Completing the top 10 was the surviving Suzuki of Alex Rins, whose teammate Andrea Iannone crashed out on the opening lap at La Chapelle.

Pol Espargaro led the KTM charge in 11th, while top rookie Hafizh Syahrin (Tech 3 Yamaha), Franco Morbidelli (Marc VDS Honda), Bradley Smith (KTM) and Takaaki Nakagami (LCR Honda) rounded off the scorers.

The remaining crashers were Scott Redding on the second Aprilia, Tito Rabat (Avintia Ducati) and Alvaro Bautista (Nieto Ducati).

Race results:

Pos.	#	Rider	Bike	Gap
1	93	Marc Marquez	Honda	41'49.773
2	9	Danilo Petrucci	Ducati	2.310
3	46	Valentino Rossi	Yamaha	5.350
4	43	Jack Miller	Ducati	6.314
5	26	Dani Pedrosa	Honda	7.419
6	99	Jorge Lorenzo	Ducati	10.355
7	25	Maverick Viñales	Yamaha	23.758
8	35	Cal Crutchlow	Honda	25.795
9	41	Aleix Espargaro	Aprilia	26.206
10	42	Alex Rins	Suzuki	27.937
11	44	Pol Espargaro	KTM	32.304
12	55	Hafizh Syahrin	Yamaha	34.962
13	21	Franco Morbidelli	Honda	37.881
14	38	Bradley Smith	KTM	38.299
15	30	Takaaki Nakagami	Honda	41.986
16	12	Thomas Luthi	Honda	45.260
17	17	Karel Abraham	Ducati	56.872
18	10	Xavier Simeon	Ducati	1'12.117
Ret	45	Scott Redding	Aprilia	17 laps
Ret	53	Tito Rabat	Ducati	17 laps
Ret	5	Johann Zarco	Yamaha	19 laps
Ret	4	Andrea Dovizioso	Ducati	23 laps
Ret	19	Alvaro Bautista	Ducati	26 laps
Ret	29	Andrea Iannone	Suzuki	-