* Westwood ends dramatic day one stroke clear

* Oosthuizen birdies final hole for a 68

* Woods trails by five after bogey-bogey finish

(Updates at end of round)

AUGUSTA, Georgia, April 5 (Reuters) - British world number

three Lee Westwood ended a day of high drama and tumultuous

swings of fortune by grabbing a one-shot lead in Thursday's

opening round of the Masters.

The straight-hitting Englishman, who has yet to win a major

title, fired a five-under-par 67 at a rain-softened Augusta

National where tough pin positions posed all sorts of problems

for the game's leading players.

Westwood birdied the par-four 17th, then parred the

difficult 18th to edge one ahead of South African Louis

Oosthuizen, who stormed up the leaderboard with four birdies in

the last five holes, and ice-cool Swede Peter Hanson.

Pony-tailed Spaniard Miguel Angel Jimenez, Italy's Francesco

Molinari, Britain's Paul Lawrie, Americans Ben Crane, Bubba

Watson and Jason Dufner carded 69s while tournament favourite

Tiger Woods eked out a level-par 72 after bogeying 17 and 18.

Westwood, who finished second here in 2010 when he also

opened with a 67, was delighted with his strong start in the

year's first major.

"There was no weakness out there today in my game. I hit it

close, hit a lot of fairways and rolled in some nice putts,"

said the 38-year-old, who has six times finished in the top

three at majors.

"When this golf course is soft, it obviously gives you a bit

more of a chance, but I think they were slightly worried about

the scoring getting out of control, so they tucked a lot of the

flags away.

"You can play your way out of a tournament in the first

round, and I haven't done that, so I'm right where I want to be

and looking forward to the next three days."

Oosthuizen, who romped to a seven-stroke victory in the 2010

British Open, steadily worked his way up the leaderboard after

making a slow start before ending his round with a 20-foot

birdie putt at the 18th.

"This golf course, you've got to be very patient," the

29-year-old said after covering the back nine in three-under 33.

"I played really well at the end."

BRUTAL TOLL

Oosthuizen may have tamed the tricky 18th in the opening

round but the hole took a brutal toll on many of the players and

both Woods and Henrik Stenson came unstuck there.

Tournament favourite Woods bogeyed the hole after driving

well left into the pine trees and Swede Stenson, who had led the

field by two shots standing on the 18th tee, wound up with an

ugly quadruple-bogey eight.

"I hit some of the worst golf shots I've ever hit today,"

four-times Masters champion Woods said after offsetting three

birdies with three bogeys. "I squeezed a lot out of that round.

"I just hung in there and grinded my way around the golf

course and stayed very patient, stayed in the moment. I could

have shot one, maybe two better, but I got a lot out of that

round."

Stenson, who won the biggest title of his career at the 2009

Players Championship, golf's unofficial fifth major, raced to

the turn in five-under 31 before picking up his sixth shot of

the day at the par-four 10th.

However his 36th birthday ended on a bitter note with his

nightmarish eight at the last which began with a wayward drive

into the trees and ended with a missed three-foot putt.

"I don't think I've ever done that," said Stenson. "You make

a little mistake and then you compound it with another one and

it just keeps on snowballing. I got the snowman in the end."

South African Charl Schwartzel, who won last year's Masters

title by two shots when he became the first champion to birdie

the last four holes, opened with a 72.

U.S. Open champion Rory McIlroy, who squandered a four-shot

lead going into the final round here last year, recovered from a

double-bogey at the first to shoot a 71.

British world number one Luke Donald returned a 75, and had

to be cleared to keep playing in the Masters after officials

investigated a mix-up over his score that turned out to be an

administrative error.

Three-times Masters winner Phil Mickelson ended a

roller-coaster day with a birdie at the last for a 74 that

included a triple-bogey seven at the 10th.

(Editing by Frank Pingue)