Former world champion Nicky Hayden dominated Friday practice for the season-ending Valencia MotoGP at the same venue where he celebrated his 2006 world title.
The Honda rider comfortably defied the rain and foggy conditions which descended upon the Spanish track.
The American clocked 1min 45.777sec in the quicker afternoon session, edging out teammate and 2007 Valencia winner Dani Pedrosa by less than a tenth of a second.
Behind the Honda duo, Yamaha made their own charge for the top with Spain's Jorge Lorenzo just two-tenths slower than Hayden.
Yamaha teammate and recently crowned 2008 world champion Valentino Rossi was fourth in the session, overcoming a crash on the final bend.
"I was lucky because it was a soft crash," said eight-time world champion Rossi.
"I was going very slowly. We tried to modify the setting to try and improve our performance but I had some problems on that corner, losing the rear on entry. It was just a small slide though, so no problem. I lost some time but that is normal.
"It is cold and the track does not have any grip so it is difficult to control the bike. Anyway, I am not far from the top, in fourth position, just two tenths off the pace and tomorrow (in qualifying) I hope to make things better."
Ducati's outgoing 2007 world champion Casey Stoner of Australia was fifth quickest despite also coming off the track.