Struggling MotoGP superstar Valentino Rossi has categorically denied that he will walk out on Ducati.

Rossi's two-year Ducati contract expires at the end of 2012, but a nightmare start to the new season prompted Rossi's first public criticism of the factory, including:

"Ducati didn't follow the direction that I indicated, but I'm not an engineer and I can't solve every problem... The problems with the bike haven't changed, and neither have my requests. It's unrideable, and it doesn't make much difference what track we are on."

Those comments spawned speculation that Rossi could quit mid-season.

Such a move seemed highly unlikely for a variety of reasons and the seven-time MotoGP champion spelt out his commitment to stay on the eve of this weekend's second round in Jerez.

"Leave Ducati? I wouldn't even think of it," quotes Rossi as saying. "We have a contract in place, and I'll give my very best right up until the end. The chances of seeing me on another bike are virtually zero."

Rossi, seventh with just one podium during a debut Ducati season spent chopping and changing parts, had high hopes for this year's 1000cc GP12, featuring the factory's first aluminium frame.

But despite a promising first test Rossi, a 79-time grand prix winner on Japanese machinery, continues to struggle with speed-sapping understeer.

The Doctor was twelfth and last of the manufacturer bikes in Losail qualifying, then limped home tenth in the race.

"Those [harsh] words were the result of my disappointment," explained Rossi. "We have been trying to solve the same problems for over a year, without success, and that weighs on you.

"But I know that Filippo Preziosi and all the Ducati guys are working hard, and soon we will have updates to try."

Rossi hopes that the new updates will be available next weekend in Estoril, or at latest during the post-race test.

Rossi, who will make his 200th premier-class start on Sunday, crashed while charging through the field early in last year's damp Jerez race, bringing down Honda's Casey Stoner in the process.