Tiger Woods of the US hits his tee shot on the eighth hole during third round play in the 2012 Masters Golf Tournament at the Augusta National Golf Club in Augusta, Georgia, April 7, 2012. [Photo/Agencies]

Tiger Woods walked away from Augusta National after Friday's second round with a load on his mind after he very nearly shot himself out of the tournament in the second round.

After opening strongly with birdies at the first and third, the former World No 1 missed a couple of short putts down the rest of the front nine as he tried to close the gap on the leaders and position himself for the weekend.

Then his game started to unravel dramatically down the back nine to the astonishment of the usual big gallery of golf fans he pulled along in his wake at Augusta National.

Particularly jaw-dropping was a wild four-iron second to the 15th that flew yards wide to the right, a duffed chip into a bunker to follow and a shanked nine-iron to the par-3 16th that resulted in Woods kicking the offending club off the tee.

By the end of his round, a frustrated Woods - the 14-time major winner whose victory two weeks ago snapped a 28-month win drought - had made five bogeys, three of them on Augusta's four par-3s, and pars on all four par-5s. He finished with a 75 to share 40th at 147.

Asked what had gone wrong from Bay Hill, where he won, to his play on Friday, the American laid the blame squarely on the drastic swing changes he has been working on with coach Sean Foley aimed at accomodating the knee and ankle injuries that laid him low last year.

"I know what to do. It's just a matter of doing it," he said.

"That's the frustrating part because I'm still creeping into my old tendencies. I've just got to stay patient with it and keep doing the reps and eventually it'll become where it's second nature.

"I have it in stretches. I get into streaks where it's really good and then I lose it for a little bit. That's obviously very frustrating."

Woods now enters the weekend eight shots off the lead and with most of the world's top players stretched out in front of him.

Even so, he believes that if he and Foley can work out how to get more consistency into his remodelled swing he could still have an outside chance of shooting for a fifth Masters title after 1997, 2001, 2002 and 2005.

At the very least, he wants to maintain the record that has seen him finish in the Masters top 10 for the last seven years - the only player to have managed that feat.

"I've been around the block for a number of years and I understand how to be patient. I understand how to grind it out and the tournament is not over," he said.

"Last year I think on the final round I made up seven shots. I can do this. I've just got to be patient.

"Obviously I've got to cut that deficit down tomorrow with a good, solid round and then got off to a quick start on the front nine on Sunday and see where that puts me."

The bookies were not convinced of his chances, installing Rory McIlroy as the new favorite at 3/1 ahead of Lee Westwood at 6/1, Phil Mickelson at 8/1, Bubba Watson and Sergio Garcia at 12/1 with Woods drifting out to 40/1.

Woods will play on Saturday alongside defending champion Charl Schwartzel of South Africa.

Agence France-Presse In Augusta, Georgia