Munoz was at two-under-par when he earned a one-stroke penalty because of a wayward tee shot at the 8th hole.

The 29-year-old Colombian, who lives in the Dallas area, then went six-under over the next four holes. He made eagles at the two par-5 holes, the 9th and 12th, and sank three-foot birdies in between.

In the middle of the fairway after his tee shot at the 18th hole – another par-5 – Munoz missed the green to the right. But he hit a nice flop shot and sunk the round-ending 12-foot birdie.

"I mean, I wanted to give myself a chance ... it was 250 (yards) to the pin into the wind. I kind of wanted to hit like a bullet, like a little draw," Munoz said.

"I knew if I want to hit it close, had to be a fade, soft-landed shot. I tried to do that. Overdid it and ended up with a 60, which is really good around here."

Adam Scott opened with a 67 to be the best of the Australians. PHOTO: Sam Greenwood/Getty Images.

Munoz also had a 60 in the opening round of the RSM Classic at Seaside in Georgia in November, although that was a 10-under score. He went on to finish third.

It was good enough for a four-stroke lead here over defending champion K.H. Lee, Mito Pereira, Peter Malnati and Justin Lower.

Kyle Wilshire, a Monday qualifier making only his third career PGA Tour start, was alone in sixth after a 65 that included a near hole-in-one when he banged the flagstick with his tee shot at the 230-yard, par-3 7th.

Lee won the 2021 Nelson at 25-under-par when his low round was a 65.

He played in the same group with Scottie Scheffler and Jordan Spieth, the major champions whose first PGA Tour events were both as teenagers at the Nelson.

Scheffler, the No.1 player in the world, and Spieth both shot 67. So did 11th-ranked Dustin Johnson, who started on the back nine with five birdies and then had four more, along with four bogeys.

It was the first individual start for Scheffler since winning The Masters five weeks ago. Three-time major champ Spieth, ranked No.9, played for the first time since his RBC Heritage victory the week after the Masters.

Wilshire, who turned pro in 2014, earned $8,000 ($A11,500) last weekend when he tied for second during a mini-tour event in Oklahoma.

The Nelson purse is $9.1 million ($A13 million), with the winner taking home more than $1.6 million ($A2.3 million) and the runner-up almost $992,000 ($A1.4 million).

After having knee surgery in 2018 and not playing well the following year, Wilshire took a job as a trash porter at his girlfriend's apartment complex for four months during the pandemic shutdown in 2020.

It was an evening job that allowed him to work on his game during the day.

"It wasn't the most glamorous job, but I wouldn't say it humbled me, but allowed me to work on my game," Wilshire said. "It kept me in good shape and I just think it made me a little tougher."

Australia's Adam Scott shot a bogey-free five-under 67 to be tied 12th, with compatriot Jason Day one behind him.