After early leader
Troy Bayliss faded with tyre problems, Haga charged to an 11 second race one win - but narrowly lost out to the Australian during a tense race two fight that eventually went in the Ducati rider's favour by just 1.4secs.
"I feel happy with my result in both races today. The first race was the perfect result; even though my tyre started to wear off I was able to take the win," said Haga, who dedicated victory to a friend killed while testing in Japan. "I made a minor suspension change for race two but then didn't get as good a start as I wanted because of a small mistake. This meant I had to use more rear tyre during the race to chase and challenge Bayliss. Towards the end the tyre started sliding and I just couldn't keep up the pace with Troy."
With Toseland finishing just ninth and fourth, the Japanese Yamaha star took 25 points, the equivalent of a race win, out of the Englishman's title lead - and vows to fight to the very end.
"Today has reduced the margin on my championship challenge; it has given me more potential to win and I'm now feeling more focused than ever and I'm going to push right to the end for the title," warned Nori.
"To win 25 points over Toseland isn't easy and what we did today was great," added team coordinator Massimo Meregalli. "We'll approach the next two races with a lot of fighting spirit in light of this. Nori was superb."