Leon Haslam says a misty visor in the wet race two at Knockhill curtailed his shot at a double victory weekend after feeling he had the pace with his JG Speedfit Kawasaki to dominate.

The MCE British Superbike championship leader took a flawless race one win in the dry after fending off Honda's Dan Linfoot and despite leading parts of the second race in the rain his pace rapidly dropped off over the last 12 laps.

Haslam says the visor on his Arai helmet misted up in the final third of the race which forced him to slow and drop from battling for the lead and down to sixth place.

"We've extended the championship lead over this weekend, but for me it should have been a very easy second win," Haslam said. "With ten to 12 laps to go I couldn't see anything I dropped nearly three to four seconds a lap at the end, it wasn't anything to do with the bike it was purely because I couldn't see.

"I felt good, I felt the pace I had at the front I could have gone quicker at any point but I just couldn't see.

"I'm feeling pretty confident heading into Snetterton, I have a test in between in Japan but we will take the positives from this weekend."

Despite the missed opportunity of taking a double Haslam still extended his BSB championship lead to 13 points while maintaining his one-point advantage in podium credits over Shane Byrne.