Nori Haga's bid to win his first FIM Superbike World Championship title suffered a blow as he qualified 10th in Portugal.

Haga holds a 10 point lead over closest rival Ben Spies and the Japanese rider's agony was added to as the American was quickest in the superpole qualifying session to claim the best spot on the grid at Portimao.

The Yamaha World Superbike team rider set the best time in superpole of one minute 42.412 seconds.

Spies will be joined on the front row by the Haga's Italian team-mate Michel Fabrizio who could do him a favour by beating the American in both races, reducing the number of points he can score.

Also on the front row are British pair Shane Byrne and Jonathan Rea, Byrne qualifying the Sterilgarda Ducati in second and Rea the Hannspree Ten Kate Honda in fourth.

Leon Haslam heads the second row on the Stiggy Racing Honda from the Aprilia of Max Biaggi, Fonsi Nieto (Ducati) and the BMW of former champion Troy Corser.

Haga will be joined on the third row by Jakob Smrz (Ducati), Sylvain Guintoli (Suzuki) and Carlos Checa (Honda).

Leon Camier, who recently won the British Superbike title, was 13th fastest for Aprilia.