IRVING, Texas, May 16, 2013 (AFP) - Bradley's sizzling 10-under par round came despite two bogeys on the TPC Four Seasons Resort course, where he took advantage of a rain-softened course to set an early target that no one could match.
South African Charl Schwartzel had seven birdies and no bogeys in his seven-under 63, which gave him sole possession of second place.
"I birdied more holes than I didn't, which is rare," Bradley said. "It was just an explosive type of round."
The former PGA Championship winner said playing partners Jason Dufner and Matt Kuchar kept the round relaxed.
"Just a really fun round," Bradley said. "Kind of felt like a Saturday morning round with my buddies."
The 60 ties the tournament record for a low round held by Sam Snead and Arron Oberholser, who shot their 60s on different courses.
Cameron Beckman, Justin Leonard and Charlie Rymer shared the TPC Four Seasons course record of 61.
Bradley, the 2011 Byron Nelson Championship winner, notched the lowest round of his PGA Tour career, improving on his previous best of 63.
He teed off on 10, and had five birdies in his first seven holes. After back-to-back bogeys at 18 and one, he played his last seven holes in eight-under par, including an eagle at the par-five seventh.
Schwartzel, playing the tournament for the first time, also benefitted from a morning tee time.
"You couldn't ask for much better," he said of the conditions. "Seems like you don't get many of those opportunities, so being out here first was a bit of an advantage."
Schwartzel hit every green in regulation as he matched his low round on the US PGA Tour. He also shot 63 in the final round of last year's World Golf Championships-Bridgestone Invitational.
"There were a few flags tucked away," Schwartzel said. "But with the greens being soft, you could spin it into the corners."
Sweden's Robert Karlsson and Americans Ted Potter and Harris English were tied for third on 64. It was a further shot back to Argentina's Angel Cabrera, Colombian Camilo Villegas and American Ryan Palmer.
Villegas eagled the par-five 16th to get to eight-under, but he closed with a double-bogey at 17 and a bogey at the last.
Chinese prodigy Guan Tianlang, trying to make his third cut in as many starts on the US PGA Tour, carded an even-par 70 that included two birdies and two bogeys.
The 14-year-old, who earned low amateur honors at the Masters as the youngest player ever to tee it up at the year's first major championship, was tied for 77th.