Valentino Rossi finished the first day of the second post-season test of 2008 by setting the second fastest lap time, behind Dani Pedrosa, at Jerez - but was most pleased to have set that lap on a prototype version of the 2009 YZR-M1.
Jerez marks the last opportunity to gather MotoGP track data before the first test of 2009, at Sepang in February, and Rossi is eager to make provide Yamaha with as much guidance as possible.
Clear skies and a cold wind meant track temperatures were very cool in the morning and Rossi chose to wait until 1.30pm, when the newly-resurfaced track had warmed up slightly, to begin.
The six time world champion went on to complete 20 laps on a 2008-spec bike and 20 on the new 2009 prototype M1, on which he set a fastest lap 0.610sec behind Pedrosa.
"I am happy about this first day because my performance has been good from the beginning and I have been fast all day," declared The Doctor. "Unfortunately it's been quite cold and there was only three hours when it was possible to go fast, but we were able to get quite a lot of work done in this short space of time.
"We have tried some different things on the old 2008 bike and we were able to make some improvements and then we also tested several new things on the prototype bike, and I am happy because I did my fastest lap with this bike."
As per the new single-tyre rule there are just two front and two rear specifications available for the test, with the riders supplied with two tyres of each specification, making eight in total.
"Bridgestone have brought good tyres here; so far I don't see any problems with the new rule and it seems they're doing a good job," confirmed Rossi. "They have resurfaced the track and it has made a big difference; they have got rid of all the bumps and like this it's great fun to ride around.
"I think we will be able to go faster now. Today was very cold, especially with the wind so now I hope it's a bit better tomorrow and that it doesn't rain because we have a lot more work to do and I would like to improve my lap time a bit more," he concluded.
Rossi's Fiat Yamaha team-mate Jorge Lorenzo was third fastest, one second behind the Italian.