Henrik Stenson set the clubhouse target on day two of the US PGA Championship as he went in hunt of a second Major Championship in as many weeks.
The Swede claimed The Open Championship 12 days ago in spectacular fashion with a closing 63 and he brought that form with him to Baltusrol Golf Club with two opening rounds of 67.
Stenson had some serious company at the top of the leaderboard, however, with 2010 champion Martin Kaymer and Patrick Reed both also in the clubhouse just a shot back.
Overnight leader Jimmy Walker was also at five under having played two holes of his second round, alongside Emiliano Grillo who picked up a birdie on the second hole.
Stenson's win at Royal Troon came just three weeks after he won the BMW International Open and the 40 year old is now 30 under for his last eight rounds at Major Championships.
Beginning the day two shots behind Walker, he got off to a poor start as he bogeyed the 12th and 13th but an approach to three feet for an eagle on the par five 18th sparked his round to life.
Stenson was zoned in on his irons and put his next three approaches inside 15 feet to make birdies on the first and third before a wedge to tap-in range on the eighth gave him the outright lead.
Kaymer is another man in form with four top tens in his last seven European Tour events but he too had to overcome a poor start with bogeys on the first and third. He remained two over for his round with four to play but birdies on the 15th, 16th and last saw him sign for a 69.
Reed began the day five shots off the lead but birdies on the 11th, 14th, 15th, 18th - courtesy of a stunning bunker shot - and second gave him a share of the lead. The American then made two birdies and two bogeys on the way home to record a 65 which equalled the low round of the week so far.
England's Ross Fisher was among the very late starters in the group at four under and he was joined by Hideki Matsuyama who picked up three shots in his first four holes.
The later starters had the opportunity to post low scores after torrential overnight rain had softened the course up, with 40 minutes of play lost due to flooding early in the morning.
World Number Three Jordan Spieth was three shots off the lead after a 67 that saw him turn in 32 from the tenth but drop a shot on the seventh after finding some serious trouble off the tee.
Alex Noren and Louis Oosthuizen were in the group at two under, one clear of Andrew Johnston.
