First round leaderboard:-10 K Bradley-7 C Schwartzel (Rsa)-6 T Potter Jr-6 H English-6 R Karlsson (Swe)TEXAS. Former champion Keegan Bradley shrugged off two bogeys around the turn to set a course record with a blistering 10-under-par 60 in Thursday’s opening round of the Byron Nelson Championship in Irving, Texas.Taking advantage of preferred lies on a rain-softened layout at the TPC Four Seasons Resort Las Colinas, the 26-year-old American piled up 10 birdies and an eagle at the par-five seventh to grab a three-shot lead in the PGA Tour event.Winner here in 2011 before going on to claim his first major title at the PGA Championship just three months later, Bradley covered his final nine holes in six-under 29 after storming home eagle-birdie-birdie.Former Masters champion Charl Schwartzel of South Africa opened with a seven-birdie 63 while Americans Harris English and Ted Potter Jr. and Swede Robert Karlsson carded 64s."Today I matched up unbelievable ball-striking with great putting, which is very rare,” Bradley told Golf Channel after hitting 15 of 18 greens in regulation and totalling only 24 putts on a course softened by overnight rain.Bradley tied the tournament record of 60 held jointly by Sam Snead (1957) and Arron Oberholser (2006) while improving on the course record of 61 shared by Cameron Beckman, Justin Leonard and Charlie Rymer.South African world number seven Louis Oosthuizen, the highest-ranked player in this week’s field, opened with a four-birdie 67 while Germany’s former world number one Martin Kaymer returned a 68.Defending champion Jason Dufner, who sensationally clinched last year’s title by one shot after sinking a 25-foot birdie putt on the 72nd hole, carded a level-par 70 playing in the company of fellow Americans Matt Kuchar (69) and Bradley.China’s 14-year-old Guan Tianlang, who made his second consecutive cut on the PGA Tour at the Zurich Classic of New Orleans last month, also started out with a 70, offsetting two birdies with two bogeys.