PALM BEACH GARDENS, February 27, 2014 (AFP) - The two-time major champion from Northern Ireland owned a one-stroke lead over American Russell Henley and a two-shot edge over South African Rory Sabbatini, Welshman Jamie Donaldson and American William McGirt after 18 holes.
"I played really solid," McIlroy said. "It's a good ball-strikers' golf course. If you can really keep your ball in play and give yourself many birdie chances, that's the name of the game here."
McIlroy's day was a sharp contrast to that of world number one Tiger Woods, who struggled to a 71, his fifth round in a row without cracking par at PGA National.
"I hit it good enough to shoot at least three or four lower than I did," Woods said. "I had so many looks that I just missed. I hit good putts but I didn't figure out the greens as well as I needed to. I need to read them a little better than I did."
McIlroy's 27-foot birdie putt at the second and a tap-in birdie at the par-5 third ensured a strong start.
After dropping a 10-foot par putt to close the front side, he sank an eight-foot birdie putt at 10 and followed with his longest birdie putt, a 45-foot effort at the 11th.
"Eleven is a hole, especially today with the wind into it off the right you just want to try and get out of there with a four," McIlroy said. "I hit a pretty conservative second shot, but it was nice to be able to hole that putt."
- Woods' game not together -
After a six-foot birdie putt at 12 and a 12-foot birdie putt at the par-3 17th, McIlroy found a bunker with his approach at the last but blasted out to 4.5 feet and sank the concluding birdie putt.
"I didn't hit a great second shot but I hit a really nice bunker shot there and I was able to finish with a birdie," McIlroy said. "It's a hole you want to take advantage of."
Henley began his bogey-free day off the 10th tee and opened with four birdies in a row, then added others at the par-3 15th and fifth holes. He said finding the fairways was the key.
"Out here if you hit it in the fairway, it's lift clean and place you can get a good lie and I started out with a really good drive and a really good 4-iron, so it was a nice way to start the day," Henley said.
McIlroy, 24, won the Honda Classic in 2012 to capture the world number one ranking for the first time in his career.
But last year, McIlroy made a humbling withdrawal during his second round at the event, complaining of mental fatigue and a toothache. He later apologized and says he has learned a valuable lesson to play through tough times.
Difficult patches, meanwhile, continued to nag Woods, the 14-time major champion chasing the record 18 majors won by Jack Nicklaus but winless in majors since the 2008 US Open.
Struggling to combine solid putting with accurate ball striking, Woods looked to be in a fight just to make the cut after making three birdies, two bogeys and a double bogey.
"It was just one or the other, hit it good and miss the putt or scrap around and make a putt," Woods said. "It certainly wasn't together today."
Reigning British Open champion Phil Mickelson fired a 70, with two birdies and a double bogey after taking the past two weeks off.
Leading first-round scores on Thursday in the US PGA Tour $6 million Honda Classic (USA unless noted, par-70):
63 - Rory McIlroy (NIR)
64 - Russell Henley
65 - Rory Sabbatini (RSA), William McGirt, Jamie Donaldson (WAL)
66 - Brendon de Jonge (ZIM), Derek Ernst, Tommy Gainey, Brice Garnett, Matt Every
67 - Luke Donald (ENG), Zach Johnson, Will MacKenzie, Luke Guthrie, Brian Harman, Hudson Swafford, Tyrone Van Aswegen (RSA), Mark Wilson, David Hearn (CAN), Matteo Manassero (ITA), Derek Fathauer
68 - Padraig Harrington (IRL), James Driscoll, Troy Merritt, Nicholas Thompson, Boo Weekley, Adam Scott (AUS), Ken Duke, Lee Westwood (ENG) Ryan Palmer