Spain's Jorge Lorenzo led a Yamaha one-two by powering to victory over MotoGP world champion Valentino Rossi in the Japanese Grand Prix on Sunday.
Lorenzo's second win since moving up from 250cc last year gave him a one-point lead over Rossi in the world championship standings.
The 21-year-old, who had been suffering with a cold in the build-up to the race at Motegi's Twin Ring circuit, has 41 points to the Italian's 40 after two rounds.
Rossi began on pole after Saturday's qualifying had been washed out by rain and combined practice times used to determine grid positions.
However, Lorenzo roared past the six-times premier-class world champion on lap nine and finished the 24-lap race in 43 minutes 47.238 seconds, 1.304 seconds ahead of Rossi.
It was Lorenzo's second MotoGP win following his maiden triumph in Portugal last year and gave him a perfect boost before his home race at Jerez next weekend.
"It was a difficult race," Lorenzo told reporters after planting a flag reading 'Lorenzo's Land' in the gravel on his victory lap.
"I didn't have a good start but then I picked up the pace and passed Valentino. I opened a little gap but he was pushing me very hard so I had to ride to my limit to get the victory."
Honda's Dani Pedrosa, who rocketed from 11th on the grid to second at the end of the first lap, took third place following a see-saw battle with Rossi for second.
"It was a very physical race," said Rossi. "I made a great start but at one part of the race I was not able to ride like I wanted.
"I had some problems and I was not able to ride fast enough to pull away. After I fell behind Jorge I was battling with Dani.
"In the last part of the race I was able to pick up my pace and come back but unfortunately Lorenzo was too far ahead."
Ducati's 2007 world champion Casey Stoner, who won the season-opener in Qatar earlier this month, finished fourth after struggling with front brake trouble.
The Australian had a poor start from second but is only three points behind Lorenzo in the riders' standings on 38.
Rossi predicted a wide open title race with Honda pair Pedrosa and Andrea Dovizioso also in the picture.
"I think this year's championship will become very interesting," said Rossi, who had criticised the decision to hold the Japanese race in April because of the threat of rain.
"We've already had four riders battling for wins. Second place is not a victory but 20 points is important for the championship."