Tiger Woods is the favourite at Augusta

Defending Masters champion Trevor Immelman says of Tiger Woods: "Whether he's human or not is still up for debate."

Tiger Woods is the favourite at Augusta

Defending Masters champion Trevor Immelman says of Tiger Woods: "Whether he's human or not is still up for debate."

If Woods wins a fifth green jacket at Augusta National on Sunday even more people will be inclined to agree with the South African and certainly the rest of the field will be green with envy.

Nothing the World No 1 does might ever match his achievement in winning the US Open last June on one good leg, but after taking eight months off to have the bad one repaired he is seen as the man to beat again.

Finishing runner-up to Immelman ended that for 2008, but his left knee was bad then and now that he has full confidence in it again plus a win at Bay Hill two weeks ago in his third event back he feels no need to rule out the possibility for 2009.

"Well, I know I can do it I've done it," said Woods, who uniquely in golf history held all four major trophies after the second of his four Masters victories in 2001.

"It's hard for me to sit here and tell you that it can't be done because I've done it before. "It's just a matter of winning the right four at the right time, so hopefully it will start this week for me."

US PGA and Open champion Harrington is halfway towards what has been dubbed a "Paddy Slam", but Woods has underlined the size of the task facing him.

"It's not going to be easy," he warned. "I remember trying to do it myself and it's hard to peak four straight times.

"There are a lot of factors that go into it. Having your game come together, playing well at the right time and on top of that getting the right breaks. "People don't realise, just one gust of wind here or there is a shot that you don't think could cost you the tournament, but sometimes it does." Woods watched Harrington triumph at Birkdale and Oakland Hills from his Florida home, unable to hit any shots at that time.

The Dubliner, trailing entering the final nine holes on both occasions, played them in 32 shots each time and Woods was suitably impressed. "We all know he's been a wonderful player," he added. You knew a first major was going to happen he has the game to win more and, lo and behold, he wins two last year."

Harrington has the chance to send out a warning to Woods u2014 not that he is focusing on just the two of them - because he tees off for the first round today while the 14-major champion is in the penultimate group.

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