Justin Rose hit a four-under-par 66 to steal the limelight from Rory McIlroy in the Honda Classic in Florida.
Englishman Rose, 31, shared the lead with American Tom Gillis at eight under par after Friday's second round.
US Open champion McIlroy, who will become world number one if he wins on Sunday, made three birdies in the last five holes to finish one behind.
Lee Westwood (69) and Tiger Woods (68) both ended one under, as Graeme McDowell shot 64 for three under.
Rose, who started on the 10th, was 10 under at one point after taking 31 on the front nine. He added birdies on the third and fifth, but bogeyed the next two and failed to get up and down from sand on the seventh.
"I've not made that many mistakes," said Rose. "It's a course that rewards limiting the mistakes."
Northern Ireland's McIlroy stayed in contention with a 67 that included birdies on the 14th, 15th and 18th.
"I felt like I played another really solid round," said the 22-year-old.
"I had a couple of chances on the front nine and didn't take them, but I was just trying to stay as patient as possible.
"The bogey on the 13th when I had only a wedge in my hand [he hit it into a plugged lie in a bunker] was frustrating, but the finish was nice."
Former world number one Woods was in danger of missing the cut, which came at level par, but made amends for a double bogey on the fifth, his 14th, with birdies on his last two holes.
He said: "I got it going, lost it, got it going, lost it and then got it going. It was a little bit of a fight - probably the worst I've hit the ball in months.
"I figured something out with the swing the last four holes. Unfortunately it took me that long."
Westwood tweeted after his round: "Played lovely today, waiting for a few putts to drop. Can't seem to get away from @TigerWoods this week! Playing with him again tomorrow."
The round of the day came from American left-hander Brian Harman who shattered the course record by three with a 61 to reach six under.