Honda kicked off its quest to cling on to the World Supersport manufacturers' crown in style by filling three of the top four positions during opening free practice in Portugal.

Kenan Sofuoglu, a winner at Portimao on his return to the series last season, led the way after vaulting to the top of the timesheets with his last effort, the Turk putting a sizeable three tenth margin between himself and champion-elect Cal Crutchlow.

Crutchlow was the pace setter for much of the time, but had no opportunity to respond to Sofuoglu's top time. More pressingly, however, Crutchlow was quicker than the only rider who can stop him winning the title this weekend, Eugene Laverty.

The Parkalgar Honda rider was less than a tenth slower than Crutchlow, but with Mark Aitchison fourth on the Althea CBR600RR, the Japanese manufacturer is well positioned to keep the manufacturers' title out of Yamaha's hands.

Kawasaki and Triumph followed in fifth and sixth, Magny-Cours winner Joan Lascorz leading Garry McCoy, ahead of the second Yamaha of Fabien Foret. Local rider Miguel Praia, Massimo Roccoli and Andrew Pitt made it six Hondas inside the top ten.