Tiger Woods fired an ominous warning to his rivals on Wednesday when he described his quest for golfing perfection as a "never-ending battle".

The world number one, bidding for a third straight Dunlop Phoenix title in Japan this week, had a stunning 2006 PGA season, winning two majors and six other tournaments in just 15 starts.

Asked if he was in the form of his life, Woods replied, "Probably" but insisted that he would still be going back to the drawing board in the off season.

"There is always going to be tuning," Woods told reporters. "Golf is fluid -- it's always evolving. There's always something breaking down in the game.

"There's always things you can work on and improve on. It's a never-ending battle."

The American's remarkable success in 2006 was all the more astonishing as he took a nine-week break to cope with the illness and subsequent death of his father.

"This year's been two-fold," Woods reflected.

"It's been great on the course and not so good off it. Golf-wise, it's been great to have made strides and improvements."

The 12-times major winner added: "At the end of the year to play that well in major championships was great. It showed me the things I was working on early in the year were the right things."

Woods won the final two major tournaments of the year -- the British Open and PGA Championship -- after spending much of the last three years revamping his swing.

SHANGHAI DEFEAT

A run of six victories in a row was only ended at the Champions Tournament in Shanghai at the weekend when he was edged out by South Korea's Yang Yong-eun.

"Probably my two best tournaments were the two bookend tournaments in those six tournaments I won in a row, the British Open and the Amex Championship," Woods said.

"Last week, I had two good rounds and two indifferent rounds. The two indifferent rounds I made too many silly mistakes -- just mistakes that you can't make to win a golf tournament."

However, Woods was quietly confident of completing a hat-trick of wins in Miyazaki, despite a quality field including European Ryder Cup heroes Padraig Harrington and David Howell.

"A good sign is that I also had two good rounds in Shanghai and my closing round on Sunday was a nice positive way to end the tournament heading into this week," Woods said.

"I feel good about the things I was able to do on Sunday heading into this event. I hit a lot of good shots and hopefully I can continue into this week and do it all four days."

Harrington, who won the 2006 European Order of Merit, was relishing the challenge of facing Woods at the Japanese island resort.

"It's definitely a bonus to have Tiger in the field," he said. "You can judge your level against the number one in the world.

"When it comes to Sunday we'll do up the totals and see what difference is."