21 Louis Oosthuizen admits he needs to come up with a better game plan after making an “awkward” start to the Perth International at Lake Karrinyup.
Oosthuizen started strongly with three birdies in his first six holes, but he faded from that point on to finish his opening round at two-under 70.
American Peter Uihlein holds the outright lead after shooting a seven-under 65, while Frenchman Romain Wattel and Indian Shiv Kapur were one stroke further back.
Australians Brett Rumford and Scott Arnold were among a group of eight golfers at four-under.
Drawcard Victor Dubuisson struggled throughout the day, finishing with a five-over 77.
Oosthuizen left himself with a series of tricky downhill putts on Thursday, and the tournament favourite wasn’t happy with his placements.
“I hit it really well all day, but just found myself on the front nine in awkward spots on the greens,” Oosthuizen said.
“I just need to think a bit better around it. I left myself with a few shockers to try and make birdies.
“I found the places on the green you’re not supposed to be.”
Uihlein overcame tricky winds in the afternoon to post the day’s best score.
The 26-year-old’s highlight came on the par-four ninth, when he chipped in from 60 yards to snare an eagle.
“It took a nice little right bounce, and it looked like it was going right down to the flag,” Uihlein said.
“I heard it hit the flag before people stood up and started applauding.
“It’s always cool to see the delayed reaction.”
Kapur almost didn’t take to the course on Thursday because of a lingering shoulder injury.
The world No.487 injured his right shoulder while lifting his golf bag off a carousel at Singapore airport a few weeks ago, but some treatment just before his opening round eased the pain enough for him to play.
“I was really struggling on the driving range this morning with my shoulder,” Kapur said.
“The first few shots that I hit I couldn’t really hold the club at the top of my back swing.
“The chiropractor here did a great job to get me fit to play, and I popped a couple of pills.
“Sometimes when you drop expectations and you don’t think about your golf swing, it seems to work pretty well.”
Veteran Peter Senior finished at a promising three-under in his first tournament since switching to the short putter.
The 56-year-old, who won the Australian Masters in November, was forced to make the switch away from his trademark broomstick putter following the sport’s ban on anchoring.