Starting from the MotoGP row for the first time since pole in Argentina, Jack Miller was behind only the factory Ducatis of Jorge Lorenzo and Andrea Dovizioso at the end of the opening race lap at Misano.

Reigning world champion Marc Marquez then put a firm pass on the Pramac rider during lap 2, but Miller felt confident he could fight with the 'second group' for what would have been his best MotoGP result since Le Mans in May.

But his hopes were dashed when he tipped off at low speed on lap three, rejoining at the back of the field.

The Australian, who eventually finished in 18th, has struggled with his bike bottoming-out on a full fuel tank this year, but thinks preload adjustments to compensate for the extra weight caught him out.

"Small mistake by me. We went with a little more preload, dropped the front so it was more or less in the same spot, but it was just squishing the tyre a bit too much, especially with a full tank," Miller said.

"We normally do the preload thing, but we did it because yesterday in the qualifying, I was getting some bottoming, and that seemed like the logical step. But we knew we were going quite stiff in the preload rather than the spring.

"It was just a risk, and it didn't pay off for us today.

"I just got to the apex of Turn 14, you saw how slow I was, I lost the front and just couldn't hold her up. Really, really disappointed. A small mistake cost us an awesome weekend."

On where he had the pace to finish, Miller said: "I had Marc in front of me for a lap, and he didn't really gain on me. Felt pretty similar. But I think it would have been difficult to stay with him over race distance.

"Rins (4th), Maverick (5th), Crutchlow (3rd) - I think we could have stuck with this sort of group.

"I picked the bike up and the pace was still really good, with bent handlebars and a missing screen.

"I feel disappointed, let down by myself, so I'll go home and work on it, come back stronger in Aragon. We did a test there and we were really strong. We've got some of my favourite circuits coming up: Aragon, Thailand, Japan."

After set-up difficulties at some previous rounds, Miller was happy with how his year-old GP17 was working at Misano, although he's lacking some acceleration relative to the 2018 factory bikes.

"The bike was working really good all weekend. Just need to find a little bit more acceleration, and we'll be right… It's just how it is. Being on an old bike, I'm missing a bit of speed.

"You have to work your butt off in the corners, but that's the story of my life. We'll just keep working at it and hopefully sooner or later, we'll get on the thing with equal speed as the big guys."

Miller - who will have the latest GP19 at Pramac next season - is now 13th in the world championship, 3 points behind fellow GP17 rider Alvaro Bautista, who finished in ninth on Sunday.

Misano MotoGP - Rider Ratings