England's Justin Rose moved into third place by resuming the WGC-Cadillac Championship with back-to-back birdies at Doral in Miami.
Rose, fifth in last week's Honda Classic, chipped to six inches on the long tenth and then reached five under par with a 12 foot putt at the next.
The 31 year old, chasing a fourth victory in America, was only one behind Australian Adam Scott and American Jason Dufner, but then Dufner, runner-up in last year's US PGA Championship, also set off again with a birdie.
South African Charl Schwartzel also boosted his chances, the Masters Tournament winner one under after two holes and five under for the week – just two behind Dufner.
Scot Martin Laird did the same to improve to one under, while Open Champion Darren Clarke, who slumped from one under to two over with a closing triple bogey seven yesterday, parred his first three holes.
World top three Rory McIlroy, Luke Donald and Lee Westwood - one over, two under and four over respectively overnight - were among the later starters in the second round.
Rose's dream start continued with a pitch to 18 inches at the par five 12th.
A third successive birdie took him one behind Dufner again and even when he found a greenside bunker at the next, he saved par from 11 feet.
Tiger Woods, who finished his first-round 72 with a bogey, was quickly under par again, chipping to five inches at the tenth after seeing playing partners Sergio Garcia and defending champion Nick Watney hit their seconds into the water, although both escaped with par fives.
Rose did not have to wait long for his fourth birdie, converting a ten foot chance at the 16th and moving into a share of the lead with Scott, who birdied the first, and American left-hander Bubba Watson, who had five birdies in his first seven holes.
Woods holed from 23 feet for his second birdie at the long 12th and at two under was in a tie for 19th.
