MIAMI (AFP) - Australian Adam Scott, the 2013 Masters winner, fired a six-under-par 66 on Friday to seize a two-stroke lead after the second round of the WGC-Cadillac Championship at Doral.
Scott fired eight birdies, the last three of them in a row starting at the par-3 15th, to leap into the lead on 10-under 134 after 36 holes at Doral.
Northern Ireland's Rory McIlroy, dreaming of the completion of a career Grand Slam with a victory in next month's Masters, shot 65 to share second on 136 with American Dustin Johnson, the defending champion who carded a bogey-free 64.
England's Danny Willett was on 137 with two-time Masters champion Bubba Watson and fellow American Charley Hoffman on 138 and England's Paul Casey was joined by Phil Mickelson on 139.
Scott opened with back-to-back birdies, took a bogey at three and had back-to-back birdies again at six and seven. He birdied the par-five 12th before another bogey at 14 only to finish with a flourish to grab the lead.
Having ended a near two-year title drought at the Honda Classic on Sunday, Scott could become the first player to win in back-to-back weeks on the US tour since Billy Horschel in 2014 at the BMW Championship and Tour Championship.
"It was just a lot of good stuff," he said. "Enough quality shots and enough quality putts to negate a couple of mistakes out there. But they can easily happen on this golf course.
"So I'm glad there was enough of the good stuff to keep me up on top and kind of setting the pace after halfway."
McIlroy opened with a birdie but took his lone bogey at the second hole. He ran off four birdies in a row from the fifth through the par-five eighth hole, then birdied the 12th, 15th and 18th to nab a share of second.
The Northern Irishman needed just 23 putts, 10 fewer than he had on Thursday.
"I just needed to play a round without as many mistakes," McIlroy said. "The birdies were there. I've been making birdies. That's not been the problem. It's eliminating these mistakes that I've been making, and to play a round with only one bogey was really nice.
"I'm probably happier about that than the eight birdies I made out there to be honest with you, because the last few rounds, it's just been great shots mixed with poor shots."
Johnson birdied the second, sixth and eighth holes on the front nine, began the back side with two more birdies and birdied the par-three 13th plus 16 and 17 to secure his share of second place without making a bogey.
"I think the golf course is fantastic. It's in great shape," Johnson said. "The greens are perfect. But it's not an easy golf course... You can't take it easy anywhere out here."
World No. 1 Jordan Spieth had four birdies and four bogeys in an even par 72 that left him tied for 12th at three-under. Overnight co-leaders Marcus Fraser and Scott Piercy both signed for 77s to slip down the leaderboard.