Casey Stoner admitted that he was never comfortable with his Honda during the Mugello MotoGP race after only finishing eighth.
The reigning world champion lost ground with a mid-race trip off the road, and had qualified a disappointing fifth.
Although Stoner conceded after qualifying that title rivals Jorge Lorenzo and Dani Pedrosa seemed to be out of reach this weekend, he said he had hoped to at least salvage a podium from the race.
"It's definitely not the way we planned it, we thought today we could be fighting for the podium and maybe have the pace to stay with Dani," said Stoner.
"Jorge has ridden fantastically all weekend and hasn't really put a foot wrong but I think a third position would have been good today.
"However, we just couldn't get the bike working. During our last attempts in warm-up we couldn't get anything to work, we weren't very happy with the bike today and I just didn't feel comfortable."
Stoner said his visit to the gravel was partly the result of a brake issue.
"I made a mistake in the race, I had a bit of a shake exiting Turn 11 and when I arrived at Turn 12 I had no brakes," he said. "I was squeezing them as hard as I could and thought I had enough brake power to stop before the edge of the track but I had too much momentum and had to ride through the gravel trap which wasted a lot of time."
He also apologised for barging past Alvaro Bautista's Gresini Honda as he tried to regain ground.
"I'm sorry for the incident with Alvaro," said Stoner. "I went to make the pass into Turn 2 and he started to close my front off and I couldn't do anything.
"It's a disappointing end to a difficult weekend that I thought I might be able to salvage something from but unfortunately not."