By Mark Lamport-Stokes
AUGUSTA, Georgia (Reuters) - World number one Rory McIlroy launched his bid for a career grand slam of the four majors with a rock-solid par on his opening hole in the Masters first round on Thursday.
Watched by massive galleries on a glorious morning of unbroken sunshine at Augusta National, the Northern Irishman struck a superb approach shot to 10 feet and narrowly missed his birdie putt before tapping in for par.
McIlroy's playing partner Phil Mickelson, a perennial fan favorite and a three-times Masters champion, also parred the hole after two-putting from long range.
American Russell Henley and England's Justin Rose held a share of the early lead at three under in the year's opening major.
Henley, playing in his third Masters, birdied the fifth, eighth and ninth to reach the turn in 33 while 2013 U.S. Open champion Rose picked up shots at the third, fifth and sixth.
England's Paul Casey was at two under, after three holes, with reigning champion Bubba Watson among a large group at one under, the American left-hander having birdied the par-five second.
However, the Masters spotlight was likely to cast its brightest glare on McIlroy and four-times champion Tiger Woods during the first round.
McIlroy is gunning for his third consecutive victory in a major and a first green jacket while Woods is back on the prowl for a 15th major title after a two-month hiatus to retool his game.
Woods, who missed the Masters last year while recovering from back surgery, will be competing for the first time in two months after a self-imposed absence from the PGA Tour due to poor form.
The 39-year-old American is expected to attract the biggest crowds of the day when he sets off with fellow American Jimmy Walker and Welshman Jamie Donaldson in the penultimate group at 1:48 p.m EDT (1748 GMT).
"Everyone is just curious to see how he comes back," McIlroy said about Woods' return to competition after a two-month absence from the PGA Tour while retooling his swing.
"I don't think you should ever underestimate him. He's done things on the golf course that are pretty special. As a golf fan in general, I'm interested to see how he does."
Softened by recent rain, the par-72 Augusta layout is expected to favor the long hitters, though the greens are more receptive to longer approach shots, allowing more players to contend for the title.
(Editing by Steve Keating)