Rory McIlroy carded four birdies on the back nine in a four-under 67 to share the first day lead with Keegan Bradley at the PGA Grand Slam in Bermuda.
The 22-year-old US Open champion holed from 30 feet at the 12th in the two-day competition for the four winners of the year's major Championships.
Bradley posted two eagles to reach six-under but bogeyed the 14th and 16th.
Masters champion Charl Schwartzel shot a 74 and Open winner Darren Clarke slumped to a 77.
McIlroy reached the turn at two-under, despite missing a series of putts from inside 10 feet at the 6,845-yard Port Royal Course in Southampton.
He birdied the fifth after almost driving the 380-yard par four but three-putted the 11th before his round was revived by the long putt at 12.
Bradley made a serene start, firing majestic six-irons to within two feet at both the second and seventh for his eagles.
However, he missed a par putt from only a foot on the 14th, which McIlroy birdied, and the Northern Irishman reduced Keegan's lead to two shots at the next with another birdie after driving to within 10 yards of the 412-yard par-four.
The 235-yard par-three 16th was played during a brief rainstorm and McIlroy was the only one of the four players to find the green.
He parred the hole, but gained another shot after Bradley took four, while Schwartzel and Clarke both hit their tee shots into the sea and finished with triple bogeys.
Clarke, who was three-over after four holes, said: "Obviously I'm disappointed. I'm struggling with my swing and I'm struggling with my ball-striking. So, if you mix that with putting equally bad, that usually doesn't add up to a good score."
McIlroy, bidding to become the first British winner of the event since Ian Woosnam in 1991, drew level after another fine drive inspired another birdie at the 17th.
He admitted his early putting problems had been a concern and said: "It was getting a little bit frustrating because I was reading them and every time. I felt as if I was hitting the putt on the line I wanted to but it was just going nowhere near the hole.
"The greens that I have been putting on the last couple of weeks have been a little different to the greens here.
"I had not really been factoring in the grain as much but it plays a huge part on these greens. I finished really, really well so, to draw level after the first day was nice."