Marc Marquez moved a major step closer to clinching a fourth MotoGP title by winning a gripping Australian Grand Prix at Phillip Island.

The 24-year-old champion of 2013, 2014 and 2016 pulled 33 points clear in this season's standings with two races remaining after edging in front to take an exhilarating race.

Marquez was locked in an eight-bike battle for first place at one stage, with the Repsol Honda rider using all his guile to forge ahead and stay in front of a chasing pack.

Seven-time former champion Valentino Rossi took second place, just 1.799 seconds back, and the Italian's Movistar Yamaha team-mate Maverick Vinales finished third.

Marquez said: "I realised halfway through I had to attack, or they would overtake me. I have some marks on my leathers and my bike, but I was aggressive too! A crash or a zero would have been a disaster but it was time to attack and I knew it was an important race to increase the distance in the championship."

Rossi took the physical nature of the race in his stride, accepting it reflected the changing state of the sport at its highest level.

Rossi told "In the last few years, the level of aggression during races has raised a lot, especially with the young riders coming from Moto2.

"You either get angry or not, but that doesn't change anything. That's the game, if you want to play it's like that.

"It's a bit more dangerous but that's the game and if you don't want it, you should stay at home."

French rider Johann Zarco (Monster Yamaha) took fourth, with Britain's Cal Crutchlow fifth on the LCR Honda.

Marquez's main rival Andrea Dovizioso trailed in 13th, taking just three points to Marquez's 25 in a huge blow to his title hopes ahead of the final races of the season in Malaysia and Spain.