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. 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 put him 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. The prodigy caught fire after his birdie at 14 with another at 15, a foursome-best par at the par-3 16th and a birdie at the par-5 17th to match Bradley for the lead. Bradley sizzled after opening with a bogey, 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. 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. Clarke struggled from the start, opening with a bogey and following with bogeys at the third and fourth holes. He bounced back with birdies at the sixth and seventh but stumbled again with a bogey at the eighth and also tripled 16 before closing with a bogey.