Rossi concerned by tyre performance

The former world champion lost the lead when he went wide on the first lap of the race, but he recovered to second position within a handful of laps, only to lose pace later in the race and eventually fall to 10th.

"We are very disappointed because we didn't expect these problems," Rossi told Italia1 television.

"I immediately started to have problems with the rear tyre. It did get up to temperature, but then I started sliding all over: something went wrong on the right side of the tyre and it gave us a lot of problems.

"I was also very afraid the tyre would break at the end, so I slowed down a lot at the end and we couldn't do anymore than that. It's a shame because we were first and second (in qualifying) and we had worked well."

Rossi said he was increasingly concerned by the tyre situation. Bridgestone riders filled the top six places in Istanbul, with Nicky Hayden the leading Michelin user in seventh. Dani Pedrosa and Colin Edwards were both forced out in a tangle with Olivier Jacque and Chris Vermeulen on the first lap.

"Unfortunately our biggest enemy at the moment are the tyres," said Rossi.

"It would have been nice to see what Pedrosa and Edwards could have done, but I'm convinced they couldn't have done much better than me either.

"We don't know what happened to the tyre. Yesterday I was easily on the same pace as Stoner, Pedrosa was going quick too.

"I did 17 laps with the same type of tyre we had today, while today after 10 laps it started to slide massively. So what gets us is these drops of performance from one day to the next that we can't explain.

"Bridgestone today had a great advantage over us in stability, and at some points they would go so much quicker, I could see it well because I was the only one among the four Bridgestone runners up in front.

"Despite riding quick in some spots and better than them I couldn't keep up with them."