Padraig Harrington shot a 5-under 66 on Tuesday in the first round at the PGA Grand Slam of Golf, a two-round event at Port Royal Golf Course in Southampton, Bermuda.
The tournament has a field of four players: Harrington, Bubba Watson, Webb Simpson and Keegan Bradley.
Watson is in second place with a 3-under 68, and Simpson is one stroke behind him at 2-under. Bradley was the only player to shoot over par in the first round, 1-over 72.
The field is designed to be the four winners of the 2012 grand slam events. Watson won the 2012 Masters, and Simpson won the U.S. Open.
The defending British Open champion, Ernie Els, withdrew because of injury and was replaced by Harrington. Bradley replaced PGA Championship winner Rory McIlroy, who could not play because of a scheduling conflict. Bradley won the PGA Championship in 2011.
Bradley is also the defending Grand Slam of Golf champion. He won the event in 2011, which was also held at Port Royal.
The foursome tees off in the final round Wednesday at 9:30 a.m. The winner will earn $600,000 for the exhibition, which is a low payday for winning a tournament. On the other hand, finishing last will earn a $200,000 paycheck.