Peter Hanson made his only back-nine birdie with a 6-foot putt at the 18th hole Thursday, closing out a 5-under 65 for a one-stroke lead over David Duval and two others after the first round of the Byron Nelson Championship.
Marc Leishman and Tim Wilkinson matched Duval at 66.
Duval birdied his last three holes, Nos. 7-9.
The 42-year-old Duval, ranked 890th in the world 15 years after being No. 1, almost withdrew before the round because of a painful muscle issue in his right elbow.
Hanson made the turn at 5 under after shooting 30 on the front side. The Swede couldn't keep up the pace on the back nine that he hadn't played before Thursday because of travel issues and a sore back.