CHARLOTTE, North Carolina (REUTERS) - Jordan Spieth lamented his struggles with the putter after enduring a frustrating start to his quest to complete a career grand slam as Denmark's Thorbjorn Olesen took the clubhouse lead in the PGA Championship first round on Thursday (Aug 10).

The 21-year-old Olesen set the pace on four-under 67 while Spieth, the best putter on tour for much of short his career until this year, said he could not have putted any worse en route to a one-over 72 in calm morning conditions.

The Texan was a picture of frustration on the fiery, super-fast newly re-grassed Quail Hollow greens, often walking after his ball as soon as it had left the putter.

Followed by a huge gallery that included swimming great Michael Phelps, Spieth drove the ball well but could not convert his accuracy off the tee into more than a handful of birdie chances.

"I don't think I missed any short putts today. I just had really poor speed on my long ones," Spieth said after two late birdies salvaged a respectable score from what could have been a nasty wreck, and left him five strokes behind Olesen.

"I can't putt any worse than I did today," added the British Open champion.

"I burned a lot of edges. Some were good putts and some weren't. I needed those (two late birdies) from short range because it seemed like the lid was on (the hole) today."

While Spieth, 24, is seeking to become the youngest player to polish off the grand slam of all four modern majors, supplanting Tiger Woods, fellow American Brooks Koepka is looking to add to his US Open victory earlier this year.

Like Spieth, he birdied the seventh and eighth (his 16th and 17th) to cap a powerful display for a 68 matched by compatriots Gary Woodland, Chris Stroud and Grayson Murray on a course getting harder as the greens dried out under a baking sun.

Clubhouse leader Olesen curled in a 25-foot birdie at the last to set the pace.

"The first 15 holes, especially, I was driving the ball very, very well, and that made it a bit easier," said the world number 78.

"Coming in with some short irons into these greens was definitely the key to the round. I felt like I gave myself a lot of opportunities, and it was a very, very nice way to finish with that long putt on 18." Some of the pre-tournament favourites started well, with American Dustin Johnson, Japanese Hideki Matsuyama and Australian Jason Day all carding 70.

Rory McIlroy, a two-time winner at Quail Hollow, and British Open runner-up Matt Kuchar were among those with late tee times.