MotoGP champion Marc Marquez suffered his first DNF since last year's Silverstone round when he was clipped from behind by Johann Zarco in Sunday's Australian MotoGP.

The pair were part of a typically close Phillip Island front group when their paths crossed in terrifying fashion as they hit the brakes at the end of the 200mph home straight, on lap 6 of 27.

Miraculously, both riders escaped injury.

Zarco slid and bounced all the way to turn one, his cartwheeling Yamaha fortunately missing the following riders. Marquez managed to keep control of his Honda, but was forced to retire due to the damage.

"When I was on the bike, I didn't understand what happened and, honestly speaking, I was angry, because I felt some contact from the rear," Marquez said.

"I wasn't able to continue because my seat was completely broken and was moving a lot. It was impossible to ride in a good way and if it broke completely, it would become very dangerous.

"Then when I arrived in the box and I saw the video I understood what happened and it was completely a racing incident.

"At that point in the track we arrive really fast. Miller was in front, I was the slipstream behind Miller, at over 300 km/h. I braked, even a little bit late, and I just tried to stop more, but then I felt the contact, because Zarco took the slipstream from two bikes.

"Of course, you can say maybe he can consider this [slipstream], but it's a racing incident, I already spoke with him. I feel really lucky today because me and him are both OK so this is the most important thing."

The other good news for Marquez is that the incident occurred in the race after he wrapped up the 2018 title.

"Today I had the pace to win, I was concentrated, with more temperature normally our bike is working better, so I felt like we were able to fight for the victory," he said.

"I led for 2 or 3 laps, and then I said, 'now it's time to be back in the group', and I went wide on purpose in Turn 4 just to be behind, because I don't want to lead the group. And then yeah, I had the crash.

"But OK, unlucky here again, but if next year I can win the title again in Japan and crash again here, I would sign [for that]. No problem!"

The high-speed nature of the Phillip Island circuit means such scary incidents are always a possibility, but Marquez admitted the danger is part of the thrill.

"Most of the riders, if you ask which is your favorite circuit, which is your favorite corner? They will say a fast corner, or a fast circuit. Because we enjoy it more. But it becomes more dangerous.

"Why? Because the speed is so high. A small mistake, for example today with Johann, becomes a big mistake, because the speed is double the other tracks. Yes, it's a very nice circuit, it's one of my favorites, but it's true that when you crash here, you [often] get injured."

Marquez doesn't think any major safety changes are needed at the seaside circuit, but would like to see some of the grass next to the track replaced with asphalt.

"The only thing I think is try to remove the natural grass. It's not necessary to do it for all the circuit, but minimum for example - Turn 1 is OK - but Turn 2, which is all natural grass and the last two corners, because if you do a small mistake, you have the extra run-off area of asphalt.

"When the bikes go on the natural grass, they just start to fly. It's something we already removed from other circuits, and we must remove from here."

While the DNF means nothing for Marquez in terms of the riders' title, the accident probably denied Honda the chance to wrap-up the constructors' crown and - with team-mate Dani Pedrosa also failing to score - Repsol Honda is now just 16 points clear of Movistar Yamaha in the teams' championship.

Marquez will now chase his ninth win of the season next weekend at Sepang in Malaysia.