Chaz Davies (Aruba.it Racing - Ducati WSB) led the first day of practice that counts towards qualifying at Laguna Seca with a 1’23.633 lap, despite running wide at turn two near the end of a busy 45-minute second session.
Tom Sykes (Kawasaki Racing Team) rode to second place in the order, 0.156 seconds from provisional pole.
Late faller Davide Giugliano (Aruba.it Racing - Ducati WSB), who crashed at the same turn two that his team-mate Davies had run wide on, placed third.
The early Ducati/Kawasaki domination continued with runaway championship leader Jonathan Rea (Kawasaki Racing Team) fourth, and the privateer Panigale of Niccolo Canepa (Althea Racing Ducati) fifth - albeit 0.510 seconds from leader Davies.
Aprilia duo Leon Haslam (Aprilia Racing Team - Red Devils) and Jordi Torres (Aprilia Racing Team - Red Devils) went sixth and seventh.
The Laguna pairings continued thanks to the Suzuki duo of Randy De Puniet (Voltcom Crescent Suzuki) and Alex Lowes (Voltcom Crescent Suzuki) in eighth and ninth while 2014 world champion Sylvain Guintoli (Pata Honda WSB) scored the last place inside the top ten. Leon Camier (MV Agusta Reparto Corse) was 13th.
Two more pre-Superpole session will be run on Saturday, then Superpole itself with Sunday hosting the two 25-lap WSB races.