Valentino Rossi hampered by high tyre wear in Aragon Grand Prix

The early laps looked promising as Rossi quickly recovered from the pitlane start made necessary by exceeding his 2011 engine limit as he switched to the new part-aluminium version of the GP11.1. He was up to ninth within seven laps, and looked capable of catching the battle for sixth place.

But after that the Ducati rider's pace faded and he only just managed to hang on to 10th - equalling his worst finish of a very tough year.

"It was a very difficult race - we expected to have a bit better pace," Rossi admitted.

"I lost a lot of pace in the last eight laps because I had a lot of problems with the rear tyre.

"There was maybe something wrong with the tyre and the tyre was completely destroyed at the end and I had to slow down because I had a lot of vibration and it was very hard to ride the bike. With a vibrating tyre you cannot be fast like we expected or we wanted."

Rossi felt the introduction of the aluminium section had been a small improvement to the Ducati's behaviour and that this had been masked by the tyre issue - but that it was far from a miracle cure.

"It's not so bad," he said of the bike's performance. "But especially the rear grip was the main issue of the weekend.

"That became big with the race tyre. Already from the second lap I had an amount of wheelspin that we never saw during practice, so maybe the tyre was not fantastic. Also the tyre at the end of the race was completely destroyed - I've never seen it like this.

"But that's another thing, I'm not saying that with a good tyre I could have finished on the podium."

Rossi goes into the final four races on the schedule in sixth place in the standings, with third place at Le Mans his only podium finish for Ducati so far.