Rossi, riding with three broken bones in his right hand after a huge qualifying accident, braved the pain to try and secure the single point he needed to prevent Dani Pedrosa stealing second from him at the Valencian season finale.

While Pedrosa rode to victory, Rossi looked set to thwart the Spaniard when he moved into 15th place - for the final world championship point - just before the halfway mark of the 30 laps, then gained a further position soon after. But on lap 20 Rossi suffered a problem with his 'standard' mechanical-valve M1 engine and, after battling the mystery issue for two more laps, was forced to retire.

"I did everything I could in order to be on the grid today, because I wanted to try and confirm my second place in the championship, which I think I deserved," said a downbeat Rossi. "I was riding very fast, even though my bike was not perfect. When I got into 14th place, I told myself that my task was done, but I was feeling quite good and I wanted to try to pass some more riders. Unfortunately however I felt that I had a problem with my bike and I was forced to come in. Now we are checking the data to understand what happened, because at the moment it's not so clear."

"We would like to say sorry to Valentino because he made a great effort to race with his broken hand," said team director Davide Brivio. "Unfortunately a technical problem stopped him from getting the second place and we're very sad about this. Our engineers are doing everything they can now to understand what happened today, because Valentino felt that he had a problem and that the engine was not working properly. From our first analysis we are not yet sure what the problem was, so we have decided to send the engine back to Japan for further investigation."

"This final race has been a very disappointing end to a long and hard season," added Lin Jarvis, managing director of Yamaha Motor Racing. "I feel very sorry that our machine failed Valentino today and denied him the second place in the championship that he surely deserved. His ride today with a broken hand showed his fighting spirit and his passion for racing."

Rossi will miss this week's Valencia test due to his injuries and is expected to return to the track, on Bridgestone tyres, during the Jerez test at the end of November.

"I will need 20 days to fix my hand and then I will be back in Jerez to start my winter testing programme," confirmed Rossi.