Ben Spies will have his first and last shot at winning a World Superbike title in Sunday's Portimao season finale, before moving to MotoGP next season.

A stunning debut season has seen the triple AMA Superbike champion win 13 of the 26 races so far for Yamaha, but accidents and technical problems mean he will still start the final round ten points behind Noriyuki Haga (Ducati).

Haga has had his own difficulties, having been injured at Donington Park, and it is appropriate that the 2009 title will come down to a winner-takes-all scenario between Spies and Haga at the thrilling Portuguese circuit.

With such a narrow points difference between them, there is an almost endless list of finishing possibilities for each to be crowned champion - but the only one that Spies cares about is that two races wins, no matter what happens to Haga, will see him secure Yamaha's first ever WSBK crown.

"I can't wait to get to the circuit and get set up for Sunday's races," said Spies. "We've been fighting hard for race wins all year, and as a rookie on a new bike I think we've achieved some pretty good results.

“My focus is completely on going for two race wins on Sunday, I would love to be able to deliver the title for the team as they really deserve it and have worked so hard to make it possible.

“We do go well on the Portimao circuit, so I'm going to give it everything I've got to challenge Nori for the wins. There will be a few fast guys up there as always so it should be an exciting race day,” he added.

"We have only one choice, to go there and try to win both races,” confirmed team manager Massimo Meregalli. “Both the tests we've had at Portimao with Ben were really good and also I'm confident that he knows how to win both races so I think it is very possible we will have success. We can't do anything about the weather but we know Ben is ready to give it everything he's got regardless.”

Meregalli also hopes that team-mate Tom Sykes, who will leave the team for Kawasaki after Portimao, can go out on a high.

“I'm expecting Tom to push hard and try and get the podium that he hasn't managed to achieve yet this year and he will also try to help Ben as much as he can,” he said.

Spies will ride for Monster Yamaha Tech 3 in MotoGP next season, while James Toseland will move the other way and replace the Texan. WSS title favourite Cal Crutchlow will ride the second factory-backed R1 in 2010.