Australian Adam Scott and American Steve Lowery shared the lead after the first round of the Byron Nelson Championship in Texas after both shot five-under-par 65s.

Scott fired seven birdies but had two bogeys while Lowery signed for a bogey-free round. Scott, looking for his fourth career PGA Tour win but first since 2004, had four birdies on the front nine before his first bogey on the 12th.

He hit back with a birdie at the 13th only to give back another shot on the next hole but closed his round with birdies on two of his final three holes.

Lowery started with a birdie on the first and added two more on the front nine with another pair coming in. Bob Estes and Brett Wetterich are tied for third at four under, with 10 golfers a further stroke behind.

South Africa's Ernie Els carded a 68 while Luke Donald was the leading British challenger on 69.