Valentino Rossi has hit out at Marc Marquez acting as a "bodyguard" for new MotoGP champion Jorge Lorenzo at the season-ending Valencia Grand Prix and claimed the way the duo raced was "embarrassing" for the sport.

Italian Rossi led Movistar Yamaha team-mate Lorenzo by seven points heading into the race on Sunday, but was forced to start at the back of the grid after being penalised for making contact with Marquez last time out in Sepang.

Rossi fought valiantly to eventually finish fourth, but it was not enough to prevent race winner Lorenzo from securing his third MotoGP title.

However, veteran Rossi believes that Repsol Honda rider Marquez - who finished second - did not go hard enough at Lorenzo and hit out at the pair following the race.

"I did what I could but it was a strange situation having Marquez as the bodyguard of Lorenzo. It is embarrassing for the sport," Rossi said.

"Hopefully the sport's authorities will be able to sort it out. It is an ugly end to what has been an attractive championship. It has not been a true championship and this should not happen in sport.

"Everyone has seen their plan, this makes me sad and it's a very bad thing for our sport. I do not understand why a Honda rider allows Yamaha to win [the race]. I hope this behaviour in time turns against him.

"Lorenzo is a very good rider, it would be nice to battle on equal terms, but I think even he wouldn't be very happy to have won like this.

"I am sad that Marquez acted as bodyguard for Lorenzo. I had already said on Thursday, I was convinced that they would go to the end [with their plan]. I was sure they would have conspired against me.

"I don't know if Marquez protected Lorenzo because they are both Spanish, but it's sad he chose to be his bodyguard. Lorenzo has never done what Marquez did.

"But for his behaviour after Malaysia [when he attempted to join the court proceedings], he deserves to be treated like Marquez. I'm sad, a great opportunity has vanished and I did not deserve this."