By Andrew Both
CHARLOTTE, North Carolina (Reuters) - Rory McIlroy retained a four-stroke lead halfway through the final round at the $7.1 million Wells Fargo Championship on Sunday.
A day after shooting a course-record 61 at Quail Hollow, McIlroy was steady rather than spectacular on the front nine.
The Northern Irishman made tap-in birdies at both of the par-fives, but missed several other makeable putts.
A bogey at the par-three second, where he three-putted, was his first blemish since the first round.
The world number one made the turn at 19-under, while American Patrick Rodgers moved into second place at 15-under.
American Webb Simpson got within three shots after the second hole, but a double-bogey at the sixth, where he three-putted from four feet, effectively ended his chances.
(Editing by Gene Cherry)