MIAMI, March 7, 2013 (AFP) - Reigning Masters champion Bubba Watson, Sweden's Fredrik Jacobson, Northern Ireland's Graeme McDowell and Spain's Sergio Garcia matched Woods over Doral's Blue Monster layout.
Sweden's Peter Hanson and Americans Phil Mickelson, Hunter Mahan and Steve Stricker were on 67 while England's Justin Rose and Ian Poulter and Americans Keegan Bradley, Bo Van Pelt, Dustin Johnson and Charles Howell were on 68.
Woods began off the 10th tee playing alongside England's Luke Donald and World No. 1 Rory McIlroy of Northern Ireland and fired nine birdies against three bogeys, showing top form in an event he has won six times before.
"I like the venue," Woods said Wednesday. "This course has been good to me over the years."
World No. 3 Donald fired a 70 while McIlroy, a day after apologizing from walking out on the ninth hole of his second round last week at a nearby PGA event, fired a 73 despite an eagle and three birdies.
Woods, a 14-time major champion chasing the record 18 majors won by Jack Nicklaus, has not won a WGC event in his past 10 attempts but could snap that skid this week after a sizzling start.
Woods made back-to-back birdies at the par-4 11th and par-5 12th but then birdied the next two holes. He charged again with birdies at the 16th, 18th and the first two holes after the turn before taking another bogey at three.
Responding with a birdie at the par-3 fourth, Woods added birdies at the par-4 seventh and par-5 eighth then parred the par-3 ninth, standing briefly alone atop the leaderboard before his rivals joined him in the clubhouse.
Jacobson eagled the par-5 eighth and 11th holes, birdied the fifth and par-3 15th and opened with a birdie but took his lone bogey at the second hole.
Watson birdied the first two holes and last two holes of the front nine and the 15th and 16th as well.
Garcia began with back-to-back birdies, then birdied the sixth and par-5 eighth holes, the par-3 13th and par-4 17th holes.
McDowell had a bogey-free round, also starting with two birdies and adding others at the par-4 sixth, 11th, 14th and 17th holes.
Leading finishers on Thursday after the first round of the $8.5 million World Golf Championships Cadillac Championship (USA unless noted, par 72):
66 - Tiger Woods, Fredrik Jacobson (SWE), Sergio Garcia (ESP), Graeme McDowell (NIR), Bubba Watson
67 - Hunter Mahan, Peter Hanson (SWE), Phil Mickelson, Steve Stricker
68 - Keegan Bradley, Ian Poulter (ENG), Bo Van Pelt, Dustin Johnson, Charles Howell, Justin Rose (ENG)
69 - Rickie Fowler, Jason Dufner, Thaworn Wiratchant (THA), Nick Watney, John Senden (AUS), Geoff Ogilvy (AUS), Michael Thompson, Alexander Noren (SWE)
70 - Brian Gay, Scott Jamieson (SCO), Luke Donald (ENG), Russell Henley, Scott Piercy, George Coetzee (RSA), Louis Oostheuizen (RSA), Richard Sterne (RSA)