Padraig Harrington fired an impressive five-under-par 66 to take a two-shot lead after the first day of the PGA Grand Slam of Golf today.In near perfect conditions at the Port Royal Golf Course, the Irishman, who is seeking his first Grand Slam victory after two previous visits to Bermuda, reeled off a string birdies to hold off the big-hitting Bubba Watson who finished with a three-under 68.US Open champion Webb Simpson was a further shot behind on two-under 69.Defending champion Keegan Bradley propped up the four-man field with a one-over-par 72, leaving him a lot to do today in the final round if he is to retain his title.Harrington only secured his place in the field on Saturday following the late withdrawal of British Open champion Ernie Els, the 2010 Slam winner.While the Tour pros put on an entertaining show, there were relatively few spectators to watch it, the crowd much smaller than in previous years.For pictures click here..