A Qatar storm denied Valentino Rossi of the chance to complete a fifth and final day of MotoGP pre-season testing with his new Petronas Yamaha team.

But the Italian feels his work was already '85%' done and heads into the March 26-28 opening race weekend buoyed by clear progress during the previous two days at Losail.

"We wasted one day but fortunately yesterday we did all the important work," said Rossi, who was eleventh and +0.810s from Ducati's Jack Miller on the combined test timesheet.

"It's a shame because we have some other things to try, including a long run for a race simulation. But for the rest the balance is quite positive because especially in the last two days we improved a lot the bike, the grip, the feeling.

"I can ride in a better way. I was a lot faster than last year in the time attack and especially the race pace.

"The positive is that Yamaha worked in a clever way during the winter and they brought here some good things like the new chassis and aerodynamics," continued the 42-year-old. "This is very important because for me in the last years we have a lot of problem to improve.

"The second positive thing is the feeling with the new team and with all my staff [at Petronas] is beautiful, the atmosphere is good. So these two things make me happy.

"The problem is that also a lot of different riders and different bikes that are very fast and faster than last year but we try to be there.

"To understand the level we need to wait for the first race because when you are all together you have a lot of other factors. But I leave Qatar with good feelings."

Rossi, who was forced to miss two races last season due to a Covid diagnosis, also confirmed he was among those in the MotoGP paddock to have accepted the Qatar Government's offer of a vaccine.

"Yes, we did the vaccine this morning and I'm very happy because it's a great step for our normal life during the season, without having the nightmare to see somebody that who has covid and miss 2-3 races like happened to me last year," Rossi said

"I think that Carmelo with Dorna together with Qatar they give to us a big help and I'm very happy."

Rossi team-mate Franco Morbidelli, riding the A-Spec M1, was fourth on the combined timesheets.