Dustin Johnson grabbed a three-shot lead at the BMW Championship after birdieing four holes late in his third round on Saturday.
Crooked Stick Golf Club, a Pete Dye design, played tougher in round three with winds up and fairways providing minimal roll.
Johnson struggled to get anything going early, but he caught fire on the back nine, setting himself up for a chance to earn his third win of the season.
The American sits at 18 under, three shots clear of Englishman Paul Casey, after both carded four-under 68s.
