SA’s Brandon Stone birdied himself into contention after the first round of the 100th PGA Championship at Bellerive Country Club in Missouri.

Stone carded a four-under 66 on the par-70 layout‚ to leave him in a tie for third and two shots off the lead of the US’s Gary Woodland in the star-studded field.

The 25-year-old South African made five birdies and a lone bogey in tricky conditions that had some of the world’s best players struggling.

While Stone was rekindling the form that saw him win the Scottish Open in July where he fired a final round 60‚ Louis Oosthuizen withdrew 10 minutes before his tee time due to a back problem.

Stone was struggling outside the top 100 before the Scottish Open at Gullane‚ but has turned his year around with that win and is now in the mix at the season’s fourth major.

"If you had told me that a month ago I’d shoot 66 on a Thursday of the US PGA‚ I would have said you’re kind of smoking something‚" Stone said.

"I hit the ball really well and my rhythm was spectacular. I putted beautifully and rolled the ball so nicely. I managed to see a lot of the lines quite easily out there today‚ which could be quite tricky‚ especially with a little grain on the surface. I do like the putting green with a little bit of grain — it gets my eye a little bit more."

Stone switched back to a blade putter the week before the Scottish Open and has felt more comfortable since returning to the club that served him well as an amateur.

On a day when temperatures soared into the mid-30s with humidity and the greens became roughed up by spike marks‚ Stone held his nerve on the back nine as one of the late starters.

World number nine Dustin Johnson was tearing up the course on the front‚ moving to five under after 13 holes. But two bogeys in the last three holes saw him sign for a three-under 67.

"I got really lucky out there‚" Stone said. "I didn’t have a lot of lines that had a lot of spikes in them at all. I found some really pure patches of green‚ and I just saw the lines great.

"I really do enjoy a green with a little bit more grain to focus a little bit more. I didn’t feel like I was struggling with the surface at all‚ but I’m very excited to tee off at 6.45am tomorrow without a person stepping down on it.

"I don’t have the educational level of vocabulary to really describe today. It’s just fun. That’s the simplest of words to describe this experience. Every birdie you made‚ there were huge screams. I’m a kid from SA. I have nothing to do with St Louis. The spectators have obviously been incredible.

"The event itself is just so special. I mean‚ having players like Tiger [Woods] and Rory [McIlroy] and Jordan [Spieth]‚ these guys who are the best at the current moment and also the best of all time," Grace said.

"So to be here competing with those guys and kind of holding your own really shows that my game’s close to where it could be to be competing on a weekly basis."

Branden Grace fired a two-under 68 while Charl Schwartzel shot an even par 70‚ Justin Harding a two-over 72 and Dylan Frittelli returned a three-over 73.