Casey Stoner looks set to fight for a 24th and final Ducati victory on his last appearance for the team, after a strong showing in both of Friday's practice sessions at Valencia.
Fastest of all in morning practice, Stoner also led for a large part of the afternoon session, before a late lap from world champion Jorge Lorenzo relegated the Australian to second.
Stoner was the only rider to set his best lap time in the morning and revealed he'd suffered a small vibration with his number one bike.
“Not too bad a day today," began Stoner, who will ride for Honda in 2011. "We had some problems over the two sessions with a small vibration in one of the bikes and we lost some time trying to work out what it was.
"We changed to the other one and we started to improve the setting a little bit but we hadn't really got enough time or laps to really improve it. I needed basically one more run to be happy with what we have but in general we feel quite good.
"We have had two sessions with very good weather so no problems. We just need to wait and see what the weather does tomorrow but if we can improve the situation of my preferred bike we would be happy.”
Team-mate Nicky Hayden, who needs to beat fellow American Ben Spies to claim sixth in the championship on Sunday, was sixth fastest in the morning, but dropped to tenth in the afternoon.
“Obviously today was not how we hoped to start the last race of the season," he said. "We started this morning quite good I was fastest in the first minutes of the session I think and then third, second... at least near the front but then it was very difficult to really improve from there.
"I think did a low 34 in my first run but I didn't find a lot of time since then so we have to try and understand why. Anyway, to be honest the position is not good for sure but we are not so far away in the lap times apart from the first two so we will see what we can do tomorrow to improve. It was nice having two full sessions today.
"We will regroup tomorrow and try to improve. I love this track, I love this race so it's a long way from over. We'll keep pushing.”