Jorge Lorenzo, who can at least delay Casey Stoner's title celebrations with a podium finish in Sunday's Australian MotoGP, got off to a strong start with second overall in Friday practice at Phillip Island.
Yamaha's reigning world champion was 0.269sec behind Stoner in the morning session, but slipped to third behind Gresini Honda's Marco Simoncelli in the afternoon. Stoner remained fastest in FP2, but also didn't improve.
“Today I felt great in the morning but in the afternoon not as good. It was impossible to replicate the lap time from the morning," explained Lorenzo.
"We were up to five tenths slower and I'm not sure why, maybe the track conditions were different, anyway we'll see what happens tomorrow.
"We know that Casey is very fast here but today he wasn't so quick. We must try to win and if not possible fight for the podium on Sunday.”
Team-mate Ben Spies was the only rider in the top six, other than Simoncelli, to improve in FP2.
The Texan had struggled to eighth in the morning session, but some hard work by his crew delivered a more competitive set up for the afternoon - although more is needed.
“I'm feeling good today; we started this morning with both bikes not working so well so we knew we had to come up with something this afternoon," he said. "The second session we were working really well but still struggling in a few areas we need to make better tomorrow.
"I think we definitely can and if we do I can see us dropping up to half a second pretty easily. It's up to the boys; we know what the problem is we just need to work out how to fix it. As always I'm going to try the best I can to make it interesting for the fans and get up there.”