Six-time winner Tiger Woods is one of five players who carded a 6-under 66 on Thursday and sit tied for the top spot after the first round at the WGC - Cadillac Championship.

Woods is joined by Graeme McDowell, Bubba Watson, Sergio Garcia and Freddie Jacobson atop the leader board at the TPC Blue Monster at Doral.

"They had some nice pins out for us today. If you played smart, conditions were such that you could make some birdies today," said McDowell.

Watson had a chance to grab the outright lead at his final hole after his second shot at the par-4 18th landed within 18 feet, but he pushed his birdie effort just wide.

Phil Mickelson, Hunter Mahan, Steve Stricker and Peter Hanson all sit a shot back of the lead with 67s, while 2012 champion Justin Rose is among five players sharing 10th place at 4-under 68.

Rory McIlroy, coming off his second-round withdrawal at the Honda Classic last week, continued to struggle with an up-and-down 1-over 73 that included six bogeys, three birdies and an eagle. He is currently tied for 50th.

"It was a bit of a struggle," said McIlroy. "This is a work in progress, and I'm working at it and I'm staying patient."

Mahan held the early lead after a string of four straight birdies starting at the fifth made him 5-under at the turn, but the lead was shortlived as Jacobson rolled in eagle putts of 17 and 14 feet at the eighth and 10th, respectively, to jump into a tie for the top spot.

Mahan again moved ahead with his 20-foot birdie putt at the 12th, but he struggled from there, recording bogeys at the 13th, 16th and 17th around a birdie at the 15th. He did bounce back with a birdie at the 18th, though, to stay within striking distance of the lead.

Jacobson, meanwhile, followed his eagle at the 10th with four straight pars before ending his day with a birdie at the 15th followed by three more pars.

Woods was the lone leader to start on the back nine and traded birdies at the 11th and 12th with consecutive bogeys at the 13th and 14th.

After bouncing back with a birdie at the 16th, he hit the turn with three straight birdies, starting at the 18th to move to 4-under though 11 holes and within a stroke of the lead.

Woods almost scrambled for a par at the third following an errant tee shot that struck a tree, but he just missed a short chip as the ball rolled past the hole and had to settle for a bogey, dropping him two off the pace.

However, he recovered with birdies at the fourth and seventh to drop to 5- under and grab a share of second.

Woods' drive at the eighth then sailed into a bunker, but hit his third shot within a couple feet of the hole and sank his birdie putt for a share of the lead.

"I don't think we're going to get all four days here where it's this wind. It's got to switch sometime and start coming out of the east, and if it does, that's when the course starts playing a little bit more difficult," Woods said about the calm conditions. "Today was as easy as it gets around this place."

McDowell and Garcia each recorded bogey-free rounds, while Watson's lone bogey was countered by seven birdies on Thursday.

Mickelson also fired a bogey-free round that included an adventurous 17th in which he hit his drive on to a cart path, where he then chipped to within 10 feet of the pin off the concrete and converted the birdie effort to get to minus-5.

He had a chance to move into the first-place tie at the 18th, but missed an 18-foot birdie putt to remain a shot back.

Dustin Johnson held the outright lead following a 7-foot birdie putt at the 16th, which moved him to 7-under, but his drive at the 17th sailed wide to the left and after his second shot found its way into a bunker, he 2-putted for a double bogey.

He then carded another bogey at the 18th to push him two strokes off the pace.

NOTES: Jacobson recorded two eagles in a round for the first time in his 218 PGA Tour starts. He became the 14th player to accomplish the feat at the Cadillac Championship, but the first to do it in the first round since Sean O'Hair in 2009 ... Woods carded nine birdies in a round for the first time since the opening round of the 2012 BMW Championship ... Mickelson's drive at the 17th traveled 450 yards.