USPGA Tour:Taunting Tiger Woods is a precarious game but there are always those who are happy to risk the consequences and the latest is a 20-year-old Australian called Jason Day who is playing his first full season on the PGA Tour.

He has spoken in the past about his desire to "take down" the world's number one player and he was at it again yesterday on the eve of the Buick Invitational at Torrey Pines in San Diego, where Woods will make his first start of the 2008 American season before heading to the Middle East for next week's European Tour Dubai Desert Classic.

"Who doesn't want to become the number one guy in the world?" Day reiterated yesterday when asked if he went over the top with his previous comments.

"Some guys might want be out here to make some money but I have always dreamed, and it's been my goal since I was a little guy, of being the number one golfer in the world.

"I want to take down Tiger. He's the number one guy in the world."

The last player to challenge Woods in such a public fashion was Rory Sabbatini, who suggested last season that the world number one was now "more beatable than ever".

The South African's penance was as swift as it was brutal and included a nine-shot beating when the two men were paired together in the final round of last year's World Golf Championship at Firestone.

Day is a decent young player with a strong pedigree as a junior but his chances of usurping Woods in the foreseeable future are somewhere between negligible and non-existent. There is no shame in this, of course, because as the 2008 PGA tour season begins in earnest the same could be said of every other player in the world.

Woods' dominance of the Buick Invitational is complete - he is going for his fourth successive victory in the event - as is his supremacy over his contemporaries.

Last year he played in 16 PGA Tour events and won seven - a winning average of 43 per cent. The year before he played 15 and won eight (53 per cent). It is little wonder, then, that more than ever Woods' attention is focused on history and, especially, on winning all four major championships in a single season.

"It is easily within reason," he said recently on the prospect of winning the grand slam, strong words for a man usually content to let his actions do the talking.

Yet, if Woods appears to be tempting even his own anointed fate by suggesting he has a chance of winning all four majors, he is not alone.

The bookies have him at a preposterously short price of 20 to 1, odds predicated on the fact that the four major venues - Augusta National, Torrey Pines, Royal Birkdale and Oakland Hills - are all favourable courses for Woods, who has performed well on all four over the years.

Meanwhile, those who know him best insist he continues to improve - an unthinkable prospect for the likes of Phil Mickelson, who has teamed up with Woods' former swing coach Butch Harmon in an attempt to challenge Woods.

Harmon's successor, Hank Haney, spoke this week about Woods finally trusting his remodelled swing enough to erase his occasionally errant driving, the one "weakness" in his game over the last couple of years.

Woods' friend and neighbour Mark O'Meara said yesterday that the world number one had every chance of winning a grand slam this season, not least because he would have fewer distractions.

"There were probably moments last year, with Elin having the baby and the fact that he lost his dad the year before - sometimes people's focus can vary at various times of their career. I have spoken to Hank and I have spoken to Tiger through the winter and I reckon he is as focused as ever and fired up and ready to go. And knowing that he is 31 now, I'd say he is very prepared this year. He could easily win all four majors."

Buick Invitational

Venue:Torrey Pines (South and North), California.

Prize-money:€3,566,979 (€642,043 to winner).

Length:South: 7,569yds. North: 6,874yds.

Par:Both 72.

Course characteristics:Both courses finish with a par five. A severe test especially when wind blows in from the Pacific.

Defending champion:Tiger Woods.

On TV:Live on Setanta Golf, starting at 8pm.

Weather forecast:Damp and cool for first three days with last day sunny.