Last year's Valencia WSS winner Joan Lascorz got his 2009 home weekend off to an excellent start by claiming a 0.671sec advantage over his nearest rival during Friday free practice.
The Kawasaki rider lapped the stadium circuit in a best time of 1min 36.672sec during Friday's one and only Supersport track session, with Yamaha's star rookie Cal Crutchlow his closest pursuer.
Lascorz's team-mate Katsuaki Fujiwara made it two ZX-6Rs in the top three, but was over one-second from the top, with Ten Kate's Kenan Sofuoglu leading the Honda challenge in fourth place.
Sofoglu's team-mate, world champion and 2009 world championship leader, Andrew Pitt, was only tenth fastest, while Qatar winner Eugene Laverty was 14th for Parkalgar Honda. Ten Kate Honda are using '09 machines for the first time this weekend.
A fraction behind Sofuoglu was Crutchlow's Yamaha team-mate Fabien Foret – second to Lascorz last season - with Matthieu Lagrive completing the top six for Althea Honda.
Second free practice and the now single WSS qualifying session will take place on Saturday.