Marc Leishman and Cameron Smith scrambled to stay close to par in the opening round of the Olympic men’s competition at a hot and humid Kasumigaseki Country Club.

Leishman started slow with bogeys at the first and third, but strung together three consecutive birdies on 13, 14 and 15 to finish one-under par.

Smith’s round was halted after 14 holes when lightning hit at 1:55pm local time and suspended play.

The Queenslander shot three birdies and three bogeys to be even-par at the point, and four pars upon the resumption of play ensured he finished with a round of 71.

The day belonged to Austrian Sepp Straka who shot a bogey-free round of 63 to lead by two shots at eight-under par.

The 28-year-old world number 161 stunned the golf world on the opening morning as he made eight birdies to tie the lowest round shot in the Olympics.

“That’s special,” Straka said.

He headed to Tokyo after he missed the cut in six of his last seven starts on the PGA Tour and admitted that it has been hard work to get things to click.

“Those first few weeks before Travelers where I missed the cut my irons were bad, but my short game was really good,” he said.

“So, I worked on my irons a lot and then my short game got bad. So that’s when I missed the last couple cuts.

“But just changed my putting routine up a little and it worked really well, and my irons have been pretty good the last few weeks, so I felt pretty good about my game.”

Straka was not the only unlikely name high up the leaderboard.

Thailand’s Jazz Janewattananond, ranked 150 in the world, is in second place with a seven-under round of 64.

Janewattananond was T2 alongside Belgium’s Thomas Pieters and Mexico’s Carlos Ortiz when his round was interrupted by the weather delay after 15 holes.

However, he made birdie on the 18th to move to outright second.

The 120th ranked Pieters, who finished fourth in Rio, and the 61st ranked Ortiz, both finished with six-under rounds of 65.

Further down the leaderboard, Leishman lamented his slow start where he regularly found the rough and failed to sink mid-range putts throughout the front nine.

“It was not the start I was after to be over par there early on. The conditions were fairly easy, but fought back well there on the back nine,” the Victorian said.

“It’s a really important tournament to get off to a good start because if you don’t finish in the top three, it doesn’t really matter.

“Every golf tournament you have to be mentally there and not make any silly mistakes, but I think this one was even more important because of that top three - they only give out three prizes here.”

However, the second-ranked Australian is optimistic that he can rectify a slow start, just as Minjee Lee did last week at the Evian Championship.

“I’ve still got that chance, three good rounds and I can try and medal,” he said.

“If I can drive it well tomorrow I feel like there is a low score out there.”

Meanwhile, Smith lost his way after being two-under through eight holes and said he had struggled with his driver all day.

"Maybe just a bit jetlagged still. Coming from the US just last week probably didn't help," he said.

"Didn't hit too many fairways, and there's so many opportunities out here if you hit fairways.

"I struggled off the tee and that's what really hurt me today, I think."

In typical fashion, Smith was as focused on his countrymen as he was on himself.

"Marc and I are really good friends. It's nice to root for someone other than yourself every now and then," he said.

Upon the conclusion of his round, the Queenslander headed to the range for an over the phone session with coach Grant Field.

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