Jorge Lorenzo won the Japan Grand Prix on Sunday ahead of Marc Marquez meaning the MotoGP world championship will be decided in the final race of the season.
The Yamaha rider Lorenzo outperformed championship leader Marquez on a Honda, who came in second after a spectacular showdown, followed by Dani Pedrosa, also on a Honda.
Marquez now has 318 points in the championship, a 13-point gap over his fellow Spaniard Lorenzo with a maximum 25 points left in the season.
Valencia in a fortnight will be the first time in seven years that the world title has gone down to the wire.
Marquez, 20, is bidding to become the youngest ever MotoGP world champion and first rookie title winner for 35 years.
Conditions at the mountainous Motegi circuit were dry and sunny on Sunday, after dense fog and torrential rain forced the cancellation of free practice on Friday and Saturday.
In a practice session hours before the race, Marquez crashed at high speed although he walked away unscathed.