South Africa's Ernie Els fired a second-round 66 to lead the WGC-CA Championship at Doral in Miami by a shot at the halfway stage.
The 40-year-old South African is one in front of Australian Robert Allenby, whose round included a hole-in-one with a fairway wood at the 245-yard 13th.
Els finished the day at 10-under 134 for the two rounds, thanks to three straight birdies early on, in a round affected by poor weather.
Allenby has had a varied couple of rounds, with three eagles, 12 birdies, seven bogeys and a double bogey in his 36 holes.
Charl Schwartzel of South Africa made a 70 to finish at 7-under 137, along with Bob Hope Classic champion Bill Haas, who had a 66.
Padraig Harrington (68) and Soren Hansen (69) were at 6-under 138, while defending champion Phil Mickelson had a 69, six shots off the lead at 140.
Els admits that the weather did affect his round, his first intimation of it coming at the par-3 fourth.
"I'm just about to pull the club back and I just felt this chill come over. And I thought, 'What's going on here?' And the wind just changed right there," he said.
He came up short of the green and only just recorded par.
"Very, very strange," Els said. "I think the only other time I had that happen was in Scotland when the tide changed. Other than that, I've never seen that happen."