ABU DHABI, United Arab Emirates (AP) -- Rory McIlroy began 2016 with a masterful display of driving to set up a 6-under 66 at the Abu Dhabi Championship, upstaging top-ranked playing partner Jordan Spieth in the first round on Thursday.
McIlroy was two strokes behind early leader Bryson DeChambeau (64), the U.S. Amateur champion, after rolling in eight birdies in his first appearance after two months off, during which he underwent laser eye surgery.
"It's a great way to start the year," said the third-ranked McIlroy, who has been runner-up four times in Abu Dhabi.
Spieth, playing his first regular European Tour event, scrambled well to shoot a 68 but was put in the shade by McIlroy on a warm, wind-free morning in the gulf emirate.
"It was the Rory that I have seen win majors," Spieth said. "It was spectacular. It was a pretty unbelievable round on a very challenging golf course."
Spieth was unhappy with his driving on a course where length and accuracy off the tee is paramount, saying he "drove the ball short and crooked for the majority of the round."
He was even more upset at being warned for slow play as he walked off the eighth green, his 17th hole of the round. Rule officials said Spieth took too long over a putt on No. 8, although the American complained that the decision "didn't make any sense to me" and was a "bit odd."
"The guys behind us hadn't even reached the fairway, on a par 5," said Spieth, who acknowledged that he had taken extra time to line up a putt.
It was the first round since the European Tour modified its Pace of Play policy, which aims to trim 15 minutes off a round.
After a stellar 2015 in which he won two majors and the FedEx Cup title, Spieth started the new year by winning by eight shots in Hawaii.
Making only his seventh professional start, the 22-year-old DeChambeau belied his amateur status by shooting seven birdies and an eagle to lead a stellar field midway through the opening round.
DeChambeau is one of golf's characters - calling himself the "Golf Scientist," he has modified his irons to make them all the same length, he has two driver swings, he puts his balls in Epsom salts to establish which of them are slightly flawed, and wears a Ben Hogan-style flat cap.
"I'm just growing in confidence and belief every single day," said DeChambeau, who is regarded as one of the hottest young players in the sport after also becoming NCAA champion in 2015.
Henrik Stenson birdied five of his last eight holes in his first round since keyhole surgery on his right knee in December, and was alone in second place at 7 under.