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. Top-ranked Jordan Spieth was two shots further back on 68. READ MORE: Rory McIlroy says majors more important than Olympic gold “I had no expectations coming into today, free-wheeled it and pretty much hit every fairway and was able to make a couple putts,” said DeChambeau, 22. Unusually, the flat-cap-wearing physics student uses clubs that are all the same length. “It works pretty well. It helps me keep my same posture, same setup, same everything,” said the Californian. I had no expectations coming into today, free-wheeled it and pretty much hit every fairway Bryson DeChambeau “I’m trying to analyse and understand each and every aspect of the golf course and the way I played. I’ll analyse today and see what I can do better tomorrow.” McIlroy, 26, and Spieth, 22, played in a trio alongside world number six Rickie Fowler (70) that drew big crowds despite the near-dawn start. Northern Ireland’s McIlroy started the stronger, picking up four birdies on the opening six holes in his first tournament since winning November’s DP World Tour Championship , but Spieth’s two late birdies kept the US Masters champion in touch with the leaders. “There’s been times where it’s taken me at least four or five days to find the middle of the club face,” said McIlroy. “There’s been times where it’s taken me a couple of hours and I’m right back into it. This time it was closer to the latter.” Stenson, 39, had missed the cut in Abu Dhabi in each of the previous two years and was returning to competitive golf after knee surgery, but the amiable Swede showed few ill effects as he sank eight birdies between his fourth and 17th holes before bogeying the last. “The challenge is walking 18 holes a day,” said Stenson. “It’s a bit of a grind, especially for my foot, but knee feels pretty good, and I’ve just got to try and pace myself.” South Africa’s Branden Grace (66) is tied with McIlroy for third, English duo Andy Sullivan and Richard Bland made 67 and Spieth is one of five players on 68.