Vijay Singh, armed with a revamped swing and a new fitness trainer, is eager to return to winning ways in his title defence at this week's Mercedes-Benz Championship.

The former world number one has not tasted victory on the PGA Tour in nine months and is determined to erase memories of a largely frustrating 2007 campaign. "Last year I was very disappointed in the way I played," Singh told reporters in the build-up to the 2008 PGA Tour's opening event.

"Although I had two wins, I was really very discouraged in the way I played in the mid-season and during the majors. The two wins happened very early in the season, in the first three months, and the rest of the season was pretty cold for me."

Singh clinched the Mercedes-Benz Championship by two shots in Kapalua last January before winning his 31st PGA Tour title two months later at the Arnold Palmer Invitational. Despite close calls at the Wachovia Championship in May and the Canadian Open in July, he failed to add to his trophy cabinet.

Although Singh ended the 2007 season third on the PGA Tour money list with earnings of $4,728,376, he has been working hard to revamp his swing and improve his fitness. "The position on top was very low, very flat and laid off and that's pretty much the worst place I want my golf swing to be," said the Fijian.

Singh faces a strong challenge this week on Kapalua's hilly, par-73 Plantation Course that brings together the title-holders from the previous PGA Tour season. Although Woods, British Open champion Pádraig Harrington and Phil Mickelson have opted not to play, the 31-man field includes world number three Jim Furyk, fifth-ranked Steve Stricker and South Korea's KJ Choi (ninth). Also competing are Masters champion Zach Johnson and Argentina's Angel Cabrera, winner of last year's US Open.