Woods trails leader Westwood by five after battling 72 at Augusta

(CNN) -- Tiger Woods trailed first-round leader Lee Westwood by five shots after battling to a level-par 72 in the opening round of the Masters at Augusta National Thursday.

The former world number one, bidding for his 15th major title but first since 2008, came into the tournament as favorite after his victory in the Arnold Palmer Invitational last month.

After Palmer, celebrating the 50th anniversary of his 1962 Masters win, and two other legends, Gary Player and Jack Nicklaus performed their ceremonial starter duties, the world's elite golfers began their bids for glory in the season's opening major.

Woods, among the morning starters, hit two snap hooks at his opening two holes, both times ending in the trees to the left of the fairway.

But showing typical fighting qualities, the four-time Masters champion, saved par on each occasion and then went one-under by holing a nine-foot putt for birdie on the third.

A further birdie on the 10th saw Woods move up the leaderboard, but he could not take advantage of either of the par-fives coming home.

His tee shot on the 17th left him out of position and after finding a greenside bunker he dropped his first shot of the day.

The 18th brought further problems and he was forced to take a drop from the trees before missing the green with his third shot.

Woods conjured up a superb shot from off the green and holed the putt for a bogey five to avoid going over par for the day.

He admitted after his round that he had been struggling to find his best form.

"I didn't hit it very good," he told Sky Sports. "I squeezed a lot out of that round, one of those rounds when I had to fight."

With the course wet from thunderstorms which hit the American South, organizers compounded the difficulty by setting difficult pin positions.

"It was brutal out there," said Woods.

England's Westwood, a later starter, made a superb start in his bid for a first major title.

The world No. 3 had four straight birdies from the fifth to turn in 32 and his only dropped shot came at the 10th.

Further birdies at the 13th and 17th saw him card a 67 to lead South Africa's 2010 British Open champion Louis Oosthuizen and Sweden's Peter Hanson by a shot.

Henrik Stenson looked set to set the first-round pace as he stood six under through the 15th, but he bogeyed the 16th and worse was to follow at the last.

Finding a similar place in the trees as Woods, the Swede made a mess of his recovery and eventually three-putted for a quadruple-bogey eight to take him back to one-under 71.

Defending champion Charl Schwartzel of South Africa opened with a level par 72 while world No. 1 Luke Donald finished with a disappointing 75, the same mark as three-time champion Phil Mickelson.

World No. 2 Rory McIlroy, like Woods favored for eventual victory, sustained his challenge by finishing with two birdies to card a challenging 71.

The young Northern Irishman, who led going into the last nine holes at Augusta last year before a disastrous collapse, started with a double bogey, but kept his composure to stay in the hunt.