Never higher than tenth during his five previous track appearances as a Ducati MotoGP rider, Valentino Rossi ran fourth fastest during the middle stages of testing at Sepang on Tuesday.

But by the time the track closed at 6pm, signalling the end of the first day of the second 2011 MotoGP test, the seven time MotoGP world champion had been pushed back to ninth, 1.012sec from Repsol Honda's Casey Stoner.

It was still arguably Rossi's best day as a Ducati rider to date - and certainly the first time that he has finished a day of testing as the leading Desmosedici.

"We can be satisfied with today as a first day, because we're a second from the top, like we were at the end of the first test but without trying a late 'time attack' with the soft tyre like the others did," said Rossi.

"For the most part today, I was between fifth and sixth place, which is the goal we had set. I'm still losing about three tenths due to the shoulder [which he rates at 50% power], because I'm still stronger in the left turns, whereas I'm normally the opposite; the rest we'll have to find by working on the bike.

"The bike has improved and we have decided which direction to take. We had some doubt between two different settings, but today one bike was a lot faster than the other.

"One bike had a 'Ducati setting', the other we tried to modify for better turning. But we decided to continue with the 'Ducati setting'. We call it 'Ducati setting' because it is a more standard setting.

"That will now be our base to work from. Tomorrow we will have two bikes like this and some other cards to play to improve the performance.

"I'm also happy because we can use the hard tyres that last time we had a lot of problems with here. It was a disaster. We put more pressure on the tyre today with some different settings in the shock and we can improve this further.

"We have a lot of work to do, because the distance to the front is not '0', but we have some ideas."

With half of the eight days of 2011 pre-season testing gone, Crash.net asked Rossi to list the strong points of the Ducati relative to the Yamaha:

"I like the bike in braking. It is very stable. The bike is very strong from the beginning with the cold tyre and I have big acceleration. The engine is very strong. These are the good areas.

"Now we have to improve change of direction, turning, also under full throttle."

Aspar's Hector Barbera was the second fastest Ducati rider on Tuesday, 0.646sec behind Rossi in eleventh. Rossi's factory team-mate Nicky Hayden was twelfth fastest.