The tournament, which was canceled last year following the tragedies of September 11th, returned to action at Mount Juliet Estate. Mike Weir, the winner in 2000, posted a five-under 67 on Thursday to finish two shots back along with Vijay Singh, Chris DiMarco, Jerry Kelly, Gary Evans and Retief Goosen.
'This is a big event,' said Woods. 'This is the best players in the world. I think it's an echelon just below the major championships.'
With the 34th Ryder Cup Matches approaching, Woods seems well on his way in terms of preparation. The top player in the world collected seven birdies with no bogeys to lead after his first round of competitive action in Ireland.
Woods started with a birdie at the fourth after he landed an 8-iron six feet from the cup. He hit his tee shot inside three feet for birdie at the par-3 sixth and drained a 20-footer at the seventh to make it two in a row.
At the par-4 13th, Woods hit his approach to 15 feet for birdie and followed with a birdie at the very next hole to reach 5-under.
Woods grabbed a share of the lead with a birdie at the par-5 17th after he chipped within six feet of the hole. On 18, Woods hit a six-iron to the back of the green. He ran home the 25-foot putt for birdie to stand alone atop the leaderboard.
'I felt like I hit the ball really well today. I hit a lot of good iron shots, made a lot of putts,' said Woods. 'I think the golf course is playing absolutely gorgeous out there. The fairways are perfect. The greens are the best greens we've putted on all year, including the majors. These things are absolutely pure. I can't be too disappointed with 65.'
With days remaining before Woods will join his teammates to defend the Ryder Cup at The Belfry, the 26-year-old is focused on the task at hand.
'I'm not saying the Ryder Cup is not important,' said Woods. 'It's a completely different animal. I enjoy playing. I don't enjoy the lead-up to the Ryder Cup, because we're taken out of our normal routine.'
Niclas Fasth was the best of the European Ryder Cup players on Thursday. The Swede carded a bogey-free 68 to finish alongside Kenny Perry, Jose Maria Olazabal, Scott Verplank, Justin Leonard, Jose Coceres, Bob Estes, Nick Price, Ernie Els and Craig Parry, who won the WGC-NEC Invitational in August.
Kevin Sutherland, who captured the WGC-Match Play Championship in February, was one shot further back. Sutherland was joined by Fred Funk, Stephen Leaney, Stuart Appleby, Davis Love III, Sergio Garcia, Rocco Mediate, Jeff Sluman, Padraig Harrington and Jim Furyk at 3-under-par 69.
Phil Mickelson birdied four of his first five holes, but a double-bogey at the par-3 third kept the left-hander from making a serious charge for the lead. Mickelson added three more birdies on his round to go along with three bogeys for a 70.
Mickelson was joined by PGA Championship winner Rich Beem, Adam Scott, Eduardo Romero, Brad Faxon and Len Mattiace in a tie for 30th.
Full-field scores from the WGC-American Express Championship