A broken motorcycle seat has dramatically ended Australian Jack Miller's attempt to claim the 2019 MotoGP opener in Qatar.

Key points: Miller ripped the seat from his Ducati on the second lap of the race

Miller ripped the seat from his Ducati on the second lap of the race He said the seat had not stuck well enough to the bike's painted subframe

He said the seat had not stuck well enough to the bike's painted subframe He eventually retired due to the damage his change in riding style did to his tyres

Miller was second during the second lap of the race when the seat on his GP19 Ducati broke.

In response, Miller stood up on his bike and removed the seat, flinging it "right into the middle of the pack," in the words of television commentator Steve Day.

Thankfully, all of the riders around Miller avoided the debris.

In the time it took to remove the seat, Miller dropped 10 places, and although he persisted for another 10 laps, he eventually had to retire.

Miller threw the bike seat on the track. ( Supplied: Fox Sports )

Miller, who qualified in fourth for the race, told Crash.net the seat had not stuck well enough to the painted subframe of his bike.

"I grabbed it and threw it, but essentially once the paint and seat had been ripped off, the carbon itself is like ice and our arses have got no grip on them," he said.

"I was trying to manage it as best I could, trying to stay with the guys, but by the time I threw the seat off I was outside the top 10."

Miller said he had to change his riding style to accommodate the missing bike seat, which ultimately caused him to retire.

"The problem was I wasn't able to enter the corners, I would go in but my butt would slide to the outside of the seat rather than gripping, so I wasn't able to get my shoulders out so I had to sit very centrally on the bike and use a lot of lean angle," he said.

Jack Miller had qualified fourth for the race. ( AAP: David Crosling, file photo )

"Doing that I destroyed the edge of the front tyre and I started to get a lot of understeer, especially in the fast corners, then a lot of chatter and a lot of understeer just because I was using 60 degrees lean angle when you normally use 47 degrees.

"In the end I decided — when [Takaaki] Nakagami and Aleix [Espargaro] got back past me — to pull in, which was the safer option because I was probably going to crash."

The race was eventually won by Ducati Corse rider Andrew Dovizioso of Italy, riding the same GP19 as Miller, who beat reigning world champion Marc Marquez by less than 0.04 of a second for the second year in a row.