Miami - Four-time major champion Rory McIlroy fired a four-under par 68 Saturday to seize a three-stroke lead after the third round of the World Golf Championships Cadillac Championship at Doral.
The 26-year-old Northern Irishman, who hopes to complete a career Grand Slam at next month's Masters, stood on 12-under 204 after 54 holes at the Blue Monster.
Australian Adam Scott, who owned a two-shot lead over McIlroy when the day began, and US defending champion Dustin Johnson shared second on 207. Two-time Masters champion Bubba Watson, five-time major winner Phil Mickelson and England's Danny Willett shared fourth on 209.
Third-ranked McIlroy, who closed with eight consecutive pars, seeks his 12th US PGA Tour title, his first since last May at Quail Hollow, and his 20th career victory worldwide.
"It was good," McIlroy said. "The wind was coming from a different direction so it made the course play a little bit tougher. I played a solid round of golf, didn't make any mistakes. I felt really good about it. I'll have to do the same thing tomorrow."
Eighth-ranked Johnson, 31, seeks his 10th career US PGA Tour title and the first since last year at Doral.
Ninth-ranked Scott, 35, seeks his 13th career US PGA title and second in as many weeks after last weekend's Honda Classic triumph snapped a 21-month win drought for the 2013 Masters champion.
McIlroy birdied the par-5 opening hole, blasting his third shot out of a greenside bunker to four feet from the cup to set it up. He sank a seven-foot birdie putt at the fifth and blasted out of a greenside bunker to three feet with his third shot at the par-5 eighth to set up another birdie.
At the par-5 10th, McIlroy found the left rough on his approach but punched his third shot to 17 feet and sank his birdie putt to reach 12-under and seize a two-stroke edge.
McIlroy, using a new left-hand lower putting grip, had some tight par saves down the stretch. At the par-5 12th, McIlroy's second shot went way left and his third dropped into a greenside bunker, but he pitched to eight feet and saved par with his putter.
At 18, he found a greenside bunker with his approach but pitched out to five feet and made a tense par putt to extend his streak of holes without a dropped shot to 33.
"I've been comfortable over my putts and it's great to make one like that at the end to finish off a good round," McIlroy said.
Scott's run of 16 rounds at par or better, what had been the best active streak on tour, ended on a disappointing day.
The Aussie made bogey at the par-3 fourth, missing the green and a 10-foot par putt, and even when he birdied the par-5 eighth it was after a nine-foot eagle putt miss.
Scott found a bunker at the par-3 13th and missed a 7 foot par putt, but on 14 he punched out of a bunker and sank a nine-foot birdie putt. He lipped out a birdie putt at 16 and stumbled again with a bogey at 17.
Johnson, who sank a six-foot birdie putt at 16 to reach 10-under, closed with a bogey to drop back level with Scott at three adrift, but the defending Doral champion will play alongside McIlroy in the final duo while Scott and Mickelson are in the penultimate pairing.