Valentino Rossi says Ducati is lacking pace following the Sepang test, the Italian admitting he is not too optimistic the chassis issues can be solved.
Ducati concluded the second of Malaysia's tests today with somewhat sub-standard results.
The best Rossi and Nicky Hayden could manage was 11th and 12th respectively, disappointing for the pair after a positive start.
Rossi's efforts were blighted this week by flu, the six-time MotoGP champion losing an entire day's testing having to spend Wednesday in bed.
The Italian conceded he was not too hopeful on fixing the issues with the bike's chassis.
"We couldn't be satisfied with this test because we didn't reach our goals," said Rossi. "Instead, we're 1.8 seconds back, and our rhythm is also lacking. After the first day, we thought we could do it. We had started well and were able to make the bike work with the hard tyres, which is good.
"After that though, we didn't take steps forward. Although we have some good ideas for the electronics that I'm optimistic will solve those problems relatively easily, I'm not as confident about the chassis set-up. We tried hard, but we haven't yet managed it.
"I'm able to brake hard, but I'm still having trouble in mid-corner. It was definitely a disadvantage to only ride two days instead of three because we had to rush at the end and try many things in order to understand as much as we could."
Team-mate Hayden remained more hopeful about the GP11's lack in progress.
Hayden blamed no major problems, but "a combination of little details that prevented us from getting the results we'd hoped for."
The American praised his team but admitted: "We need to do better than this."