Updated

Lee Westwood is four-under par through nine holes and in the lead during Thursday's opening round of the Masters at Augusta National.

Paul Lawrie, the 1999 British Open champion, and Miguel Angel Jimenez are the clubhouse leaders at three-under 69. Francesco Molinari and Jason Dufner are three-under, but still playing round one.

Tiger Woods, a four-time Masters winner, who earned his first PGA Tour victory in almost three years just a few weeks ago, was two-under par through 16, but bogeyed 17.

A poor drive at the 18th led to an unplayable penalty. After his drop in pine needles, Woods missed the green left with his third. He pitched to four feet and converted the bogey putt to limp in with an even-par 72.

Rory McIlroy, who famously blew the lead on the back nine Sunday last year thanks to an errant drive at the 10th, double-bogeyed the first, but is one- over through seven.

Phil Mickelson, a three-time champion, who, like Woods and McIlroy is a favorite this week, is one-over through six holes.

The leader through most of Thursday's first round was Sweden's birthday boy, 36-year-old Henrik Stenson. He walked to the 18th tee at five-under par, thanks to two eagles, and two clear of Lawrie, but drove left into the trees.

Stenson punched out, but was still in the pine needles, then chunked his third. After slamming his club in frustration, Stenson knocked his fourth over the green. Add it all up, and Stenson made a quadruple-bogey eight.

"Very disappointing finish," Stenson said in a televised interview.

He fell to one-under par, where he was joined in the clubhouse by Ross Fisher, Steve Stricker, Padraig Harrington, Stewart Cink, Aaron Baddeley, Matt Kuchar and Asian Amateur Champion Hideki Matsuyama.

At the moment, everyone is trailing Westwood, who, at world No. 3, is one of the best players to never win a major.

Westwood birdied the par-five second, but lost a shot with a bogey at the par- three fourth. That was the last hiccup on the front nine for the Englishman, who finished second to Mickelson in 2010.

Westwood birdied four in a row from the fifth and had a chance to make it five in a row, but narrowly missed a birdie try at the ninth.

Westwood is by no means a lock to be the leader when the round is completed. He has Amen Corner to contend with, and after the eight by Stenson, the 18th is not playing easy.

Plus, with thunderstorms forecast for Thursday evening, the first round may be delayed and eventually finished on Friday.

Defending champion Charl Schwartzel, who became the first player in Masters history to birdie the last four holes to win, managed a 72 on Thursday.