SOUTHAMPTON (AFP) - US Open champion Rory McIlroy birdied three of the last five holes to grab a share of the lead with American Keegan Bradley on Tuesday after the first round of the PGA Grand Slam of Golf. The 22-year-old from Northern Ireland matched Bradley, this year's PGA Championship winner, on four-under par 67 after the opening 18 holes in the two-day, $1.35 million showdown of the year's four major golf champions. "To birdie three of the last five holes was great," McIlroy said. "Actually I hit the ball really well. I gave myself so many chances on the front nine and didn't really make anything. I started to hole a few putts on the back nine." South African Charl Schwartzel, the reigning Masters champion, was a distant third on 74 with Northern Ireland's Darren Clarke, the British Open winner, last after struggling to a 77. The winner after Wednesday's final round will take home $600,000, twice as much as the runner-up, with $250,000 for third place and $200,000 for last over 36 holes at the 6,845-yard Port Royal Golf Course. McIlroy, who like all his rivals captured his first major golf crown this year, showed no sign of jet lag after a whirlwind tour of China for an exhibition and a long flight that saw him arrive in Bermuda on Monday afternoon. McIlroy birdied the par-4 fifth and par-5 seventh holes. He took bogeys at the par-4 11th and par-3 13th holes but each time answered with a birdie on the following hole. "I was hitting the putt on the line I wanted to, but it was just going nowhere near the hole," McIlroy said of his early going, noting that the grains of the greens were unlike what he has played in Asia in recent weeks. The prodigy caught fire after his birdie at 14 with another at 15, then battled heavy rain for a foursome-best par at the par-3 16th and a birdie at the par-5 17th to match Bradley for the lead. "It was a bonus to par 16 and birdie 17 in that bad weather," McIlroy said. "I made up a few shots there. I'm very happy, in a good position." Winds played havoc with shots at times and rain became a factor at the finish. "That was pretty severe rain," Schwartzel said. "If it carried on raining like that for another half hour or so, it probably could have flooded the course." Bradley sizzled after opening with a 20-foot bogey putt, answering it with an eagle at the par-5 second and a birdie on the par-3 third. He birdied the sixth, eagled the par-5 seventh and closed the front nine with another birdie. But Bradley stumbled with bogeys at the par-4 14th and par-3 16th as McIlroy charged. "It was a great day," Bradley said. "I got off to a really good start and I kind of slowed down on the back, but actually still played very well. The two putts I missed I thought could have gone in, but it was still a lot of fun." Schwartzel stayed in the hunt early with birdies at the par-5 second and seventh holes, but stumbled to three bogeys in a row starting at the 12th and took a triple bogey at the 235-yard par-3 16th to fall back.