For McIlroy, Thursday's impressive start reinforced a recent pattern. The golfer from Northern Ireland has been getting out fast -- but he hasn't always been able to hang on for the win.
"Maybe it's having higher expectations going out on a Friday because you shot a low round," he told reporters, adding that he hoped to "put those expectations aside."
Tiger Woods overcame a shaky start to record six birdies and finish the day tied for 10th at three-under.
Late starters had a tougher time as winds steadily picked up.