Jorge Lorenzo admitted that he had 'forgot how to ride' during day one of the Sepang MotoGP test - when he was fifth fastest and only the third best Yamaha.
But last year's MotoGP title runner-up felt much more comfortable on the final day of the first 2010 test, when he set the third fastest lap time.
Lorenzo lapped 0.360sec behind Ducati's Casey Stoner and 0.755sec from Fiat Yamaha team-mate and reigning champion Valentino Rossi.
"I felt much better today and I was able to be fast straight away. It wasn't a big problem yesterday, it's just that after such a long break I forget how to ride a little bit!” said Lorenzo.
“I need a bit of time, but it was much better today. I'm happy about my performance and about my feeling with the new bike.
“Yamaha have made good improvements without changing the best parts of the bike and this is the best way. They have made some good modifications to the chassis and the engine and this has already improved our pace.
“We don't have many days on the bike until the start of the season so we will make the most of the time here next month to continue our good work,” he added.