Valentino Rossi has acknowledged that Ducati's MotoGP rivals have taken a 'big step' over the winter, which the Italian factory is yet to match.
Rossi, who finished seventh on his Ducati MotoGP race debut in Qatar earlier month, makes his second Desmosedici race start at Jerez in Spain on Sunday.
The #46 is the most successful rider at Jerez, having won six times in the premier-class, but a seventh victory this weekend would be a real shock as he struggles with both a healing shoulder and extracting more performance from the Ducati GP11.
“It's a difficult moment because we have different problems, the first is me and I need time to be at 100%, the second is the bike,” said Rossi on Thursday.
“I need to be in a better condition and to ride the Desmosedici in the best possible way.
“On the other side many of the other bikes, especially Honda, have taken a big step and we need to take that same step.”
Asked whether his switch to the Ducati was proving to be the biggest challenge of his career, Rossi added: “Yamaha was also a great challenge. Now I think it's a bit more difficult because the level is higher and also because of my condition. I need more time.”
Looking ahead to the weekend, he concluded: “I like this track, love the area of Andalucia, and there are always a lot of people here. Here we will try to improve on the Qatar result of seventh.”