Newly crowned champion Marc Marquez will start his final Moto2 race from the back of the grid after being punished for a clash with Simone Corsi in Friday afternoon practice at Valencia.

Corsi was sent tumbling through the gravel after contact from Marquez as the Spaniard tried to overtake.

Marquez ran off track, but stayed on two-wheels - just as when he tangled with Mika Kallio in practice for Motegi, Japan.

Marquez had not been punished for the Kallio incident, but Race Direction has taken a different view on this occasion.

"On Friday 09 November, the Race Direction decided to impose on rider Marc Marquez (SPA) a grid penalty to start from the last position for the race in Valencia on 11 November," read an FIM statement.

"Marc Marquez rode in an irresponsible manner during the Moto2 free practice causing danger to rider Simone Corsi (ITA) which is an infringement of the article 1.21.2 of the 2012 FIM Road Racing World Championship Grand Prix Regulations. No appeal was lodged. The decision of the Race Direction is final."

Marquez moved from fourth to first on his final lap of Friday practice, then walked down to Corsi's Ioda pit box to apologise.

"I had already overtaken other riders on that corner and I hadn't thought about him being one of the later brakers in the class," said Marquez of the incident.

"I passed him on the inside and then felt a touch, which was totally involuntary. I immediately looked around to see how he was and, when I saw that he had crashed, I became very worried.

"I went to apologise to him after the session, he understood and the most important thing is that he wasn't hurt. I publically apologise once again.

"Later, Race Direction decided to send me to the back of the grid on Sunday, and I can do little more than respect their decision."

Marquez finished third, from the back of the grid, at Phillip Island in 2011, after also being punished for a practice incident.

The teenager, previously a world champion in 125cc, will step up to MotoGP with Repsol Honda next year.