Rory McIlroy continued his dazzling recent form with an eight-under-par 64 to take a share of the first-round lead at the BMW Championship in Indiana.
McIlroy, who has won two of the past three US PGA Tour events, holed seven birdies and an eagle at Crooked Stick.
He is tied with Canada's Graham DeLaet and American duo Bo Van Pelt and Webb Simpson, with Tiger Woods a shot back.
"With the soft conditions, you could really shoot a number out there, and I did," said the Northern Irishman, 23.
"I took advantage of hitting the ball really well, hitting it in the fairway, which I need to do, and also hitting it long, and gave myself a lot of opportunities.
"I missed a few, but was able to make the most of them."
He began on the 10th at the Crooked Stick course near Indianapolis and closed with consecutive birdies on eight and nine after bogeying the 13th.
Woods and Fiji's Vijay Singh were one shot off the leaders, with England's world number two Luke Donald a further stroke adrift after an opening 66.