(Updates at end of round) * DeChambeau cards 64 for first-round lead * McIlroy (66) edges duel with playing partner Spieth (68) * Sweden's Henrik Stenson (65) thrives after knee surgery By Matt Smith ABU DHABI, Jan 21 (Reuters) - American amateur Bryson DeChambeau stole the limelight from golf's big guns Jordan Spieth and Rory McIlroy on his European Tour debut, seizing a first-round lead at the Abu Dhabi Golf Championship on Thursday. The self-described "golfing scientist" sank seven birdies and an eagle in carding an eight-under par 64, a stroke clear of world number five Henrik Stenson and two ahead of four-time major winner Rory McIlroy. More...