South Africa`s Branden Grace holed out from a bunker at the 18th on Saturday to grab a share of the early lead in the third round of the 97th PGA Championship.
Grace`s eighth birdie capped a near flawless eight-under par 64 that put him in the clubhouse on 12-under 204.
Second-round leader Matt Jones was at 12-under through 10 holes, with fellow Aussie Jason Day 12-under through 10 and American Tony Finau 12-under through 12.
Germany`s Martin Kaymer, trying to reprise his 2010 PGA Championship victory at Whistling Straits, also made the most of ideal scoring conditions, firing seven birdies in a seven-under 65 for 11-under 205.
Kaymer`s round included three birdie putts of 30 feet or more.
England`s Justin Rose was at 11-under through 11, with India`s Anirban Lahiri 10-under through 12.
Masters and US Open champion Jordan Spieth was slow to join the birdie blitz.
His birdie at the first was followed by nine straight pars before he birdied three in a row starting at the 10th to reach 10-under.