Adam Scott and Jason Day were left to rue poor preparation after falling way off the pace on the opening day of the World Golf Championships Bridgestone Invitational.
Scott carded a three-over-par 73 and Day a four-over 74 to be tied 54th and 63rd respectively in the 73-man field, already miles behind leader Webb Simpson.
Simpson, in his first appearance at Firestone Country Club, rode eight birdies and two bogeys to a 64 to take a one-shot lead at six-under.
Swede Henrik Stenson continued his good form to take second alone with a 65 while world No.1 Tiger Woods, a seven-time winner of the event, shared third with defending champion Keegan Bradley, fellow American Ryan Moore and England's Chris Wood after silky 66s.
Masters champion Scott chose to scale back his practice last week after the British Open and paid the price while Day's prep was hampered by a severe cold off the back of his return from Scotland.
"This week was always going to be seeing where I was at," Scott said.
"You have to pick and choose your moments to rest and I didn't do a lot of work last week, it was casual practice and playing with my mum and dad so I'm not surprised it wasn't super sharp."
Both men hit just half of their fairways and, as a consequence, struggled to find the greens in regulation.
"I was out there and I had no idea where it was going to go," Day admitted.
"It was certainly from not getting the right amount of practice after being sick. When you come to a place like this and miss fairways, it's very hard to shoot a good score."
With the PGA Championship on next week, Australia's main hopes rest on their shoulders with both looking to tighten up their game in the remaining three rounds of the no-cut event.
They hit the range for lengthy post-round practice to find some answers.
"I still want to finish well here," Day said.
"I just have to slowly chip away at it. It will obviously be tougher to win from this position but there are low ones out there. I just have to be patient and play the best I can."
Scott, while disappointed, claimed there was no cause for alarm.
"It's nothing bad. I just need to hit a few more balls and sharpen up over the weekend to be ready for next week.
"And if I hit some good shots tomorrow, who knows?"
Rounding out Australia's tough day, Brett Rumford's 76 left him tied for 70th while Australian PGA Champion Daniel Popovic could only manage a 79 on his debut on the world stage to anchor the field in 73rd.
