Koepka and Schwartzel shoot record-equalling 63s, Woodland retains lead
Brooks Koepka and Charl Schwartzel matched the lowest round in US PGA Championship history and Kevin Kisner also capitalised on perfect conditions but Gary Woodland took the clubhouse lead at Bellerive Country Club.
U.S. Open champion Koepka and Schwartzel carded magnificent seven-under 63s on the par-70 course, taking advantage of a lack of wind on a sunny day in St Louis on Friday.
Koepka missed out on matching Branden Grace's major record when he could only par the last to sit two shots adrift of Woodland, having produced a blemish-free round featuring seven birdies.
Schwartzel equalled that feat to surge up the leaderboard into a share of fourth with Dustin Johnson and Thomas Pieters, the South African dropping just the one shot at the sixth in an otherwise brilliant round.
Kisner was on course to shoot the first 61 in major history, but parred the par-five eight and bogeyed the ninth - his final hole of the day - to sign for a 64 and head into the weekend one shot off the lead on nine under.
Woodland led by a solitary shot after the first round and still held the slenderest of advantages courtesy of a four-under 66.
World number one Johnson is ominously poised on seven under following a 66 of his own, five of his six birdies coming in the last seven holes.
Francesco Molinari got off to a blistering start and the Open champion finished five shots adrift of Woodland after carding a three-under 67, with Brandon Stone one shot better off on six under.
Rickie Fowler - one shot off the lead after the first round - dropped a shot on the first, while Tiger Woods, Rory McIlroy and Justin Thomas sit just above the projected cut line ahead of their second rounds in the afternoon.