Rory McIlroy shot his lowest round of the season so far, but fellow Northern Irishman Graeme McDowell is the closest challenger to a rejuvenated Tiger Woods at the WGC-Cadillac Championship in Miami.
McIlroy, in the spotlight following his poor start to the year and controversial withdrawal from the Honda Classic last week, added a 69 to his opening 73 to lie two under par, despite missing a tap-in for par on the 18th.
But that was still 11 shots adrift of playing partner Woods, who compiled a superb 65 to go with his opening 66 for a two-shot lead over former US Open champion McDowell, who carded a flawless 67.
On a truly world-class leaderboard, Phil Mickelson was a shot behind McDowell after a second straight 67 which almost finished with a hole-in-one, while Steve Stricker was also 10 under and could come to regret giving Woods a putting lesson on Wednesday when the £5.8million event concludes on Sunday.
However, Woods was looking in ominously good form as he seeks a seventh win in the event and a 17th WGC title of his career. The 14-time major winner, joint leader overnight after a 66 on Thursday, opened with three pars before picking up shots at the fourth and fifth from close range.
Another birdie from seven feet on the seventh took him into the outright lead for the first time, while a wayward drive on the par-five eighth could not prevent another birdie after he pitched to 15ft and coaxed in a curling putt.
Out in 32, Woods also birdied the 10th, 11th and 13th before his only bogey of the day on the 14th, but that was soon followed by a 17th birdie of the week - a new career best in the opening two rounds - on the 16th and two closing pars.
McIlroy issued a full apology for his shock withdrawal last week on Wednesday, admitting the pain from a wisdom tooth and being in a "bad place mentally" was no excuse for walking off the course after playing eight holes of his second round in seven over par.
However, a full weekend working with coach Michael Bannon on a swing flaw had not done the trick, with the 23-year-old admitting there was no quick fix at hand. A two-putt birdie on the first was the ideal start, but McIlroy bogeyed the fourth and sixth before a birdie on the eighth took him out in 36.
Four birdies on the back nine raised hopes that the US PGA champion was back on the right track, but a three-putt on the 18th took some of the gloss off a good performance. Overnight joint leader Sergio Garcia (72) and Ian Poulter (70) were among an 11-strong group on six under, but Justin Rose's hopes of defending his title look to be over after he dropped four shots in his last three holes to lie four under.