Despite the first day at Oak Hill being disrupted by thunder and lightening, the soft course allowed low scoring to be made and there were plenty of golfers who took up that opportunity.
Masters champion Adam Scott has been very impressive with his major performances over the last few years. The 33 year-old Australian who finished third at the Open three week ago, now looks to be in contention once again after scoring 65, one shot off the course record. Scott fired in five consecutive birdies from the fourth hole and birdied another at the 14th, however had to make do with a bogey on the 17th.
Joint at the top with Scott is USA's Jim Furyk. The veteran also reached six under before making a bogey at the last. The 43 year-old will be looking to add to his only major win, the Open back in 2003.
Lee Westwood was so close to winning the Open at Muirfield three weeks ago after losing a two shot lead. The Englishman is bidding for his first major championship once again, finishing one shot behind the leaders on four under, alongside Canada's David Hearn.
England's Paul Casey, Americans Robert Garrigus, Matt Kuchar and Scott Piercy and Australians Marcus Fraser and Jason Day all carded three-under-par.
US Open winner Justin Rose is on two under whilst Rory McIlroy is four shots behind on one under.
Open champion Phil Mickelson had a rollercoaster round as he scored four birdies in his round but a double bogey at the 18th meant that the American would walk into the clubhouse one-over-par at the end of day one.
Tiger Woods finished in similar fashion to Mickelson, dropping two shots at the last to also finish on plus one, falling six shots behind leaders, Scott and Furyk.