Zach Johnson fired a spectacular 10-under-par 62 to take a share of the lead following the opening round of the Justin Timberlake Shriners Hospitals for Children Open in Las Vegas.
Having won the Valero Open last weekend, Johnson picked up where he left off with a brilliant bogey-free round that included five consecutive birdies over the TPC Summerlin course.
However, the 32-year-old had to settle for a share of the lead after Marc Turnesa ended his round with three birdies over his last four holes.
Johnson began on the back nine and opened with consecutive birdies before adding two more at the 14th and 16th.
He then sank five birdies in a row from the first hole and finished with another at the par-five ninth.
Turnesa picked up birdies on five of his first seven holes after also starting out at the 10th.
He had previously failed to make the cut in six of his previous eight tournaments but also enjoyed a bogey-free round on Thursday.
The duo hold a one-shot lead over a group of four golfers.
Ken Duke carded seven birdies and a eagle for a 63 to finish alongside Matt Kuchar, Nick Watney and Michael Allen.
Four more players are two shots back, including Australian Nick Flanagan, who collected nine birdies before bogeying the ninth – his final hole.
Chez Reavie, Kevin Na and John Mallinger are at eight-under, while defending champion George McNeill is five shots back following a 65.