Technically counted as a new course record (with two new tees in place at Castle Hill Country Club since last year’s event, and a complete course redesign since the days of Paul Gow’s 60 in 2000), O’Donovan leads by one from fellow Sydneysiders Nathan Barbieri and Kiwi Nick Voke.
 
LPGA Tour player Cassie Porter is another shot further back on 7-under in her adopted hometown, with Victorian amateur Jazy Roberts impressing tournament host Peter O’Malley during her 6-under opening round to sit tied fifth with Louis Dobbelaar.
 
“I guess for some people it would help them and it definitely seemed like it helped me today,” O’Donovan said of his all-Avondale Golf Club first round trio alongside Christopher Fan and Rachel Lee.
 
“It’s a very, very weird feeling playing with people I play with a lot in a tournament, especially in a professional tournament, because usually I'm playing with people I've never met before and it makes me kind of zone in a little more.”
 
It was a similar sentiment from Barbieri, who played Thursday’s first round with good friend James Conran and Kristalle Blum; Barbieri’s good feelings further extended by the company of Josh Greer, Jack Thompson and Dobbelaar staying at his family home in Sydney’s North West.
 
“I mean, it's always good staying in your own bed,” Barbieri said.
 
LPGA Tour player Cassie Porter sits in third on 7-under after the first round. (PHOTO: Brett Costello / Golf Australia)
 
“We've got a few boys this week [staying at home], so it's a good vibe. And this is very similar to where I play at Monash. Kikuyu. It's slopey greens. I feel very comfortable.”
 
Barbieri believed his only error came off the 10th tee, where he managed to recover for par, while O’Donovan's round of 63 remarkably included a dropped shot at the par-4 sixth hole.
 
Voke and Porter were the only players in the first handful to manage bogey-free rounds; Voke’s good play coming as he focuses his energies elsewhere, including helping friend and golf influencer Luke Kwon.
 
“It almost seems less significant out here,” Voke said.
 
“The side things that I am doing, I really enjoy it and I'm with really cool people … It's nice having my identity fully as just a pro golfer.”
 
For Porter, the nice side was a bounce back from her less than ideal start to her LPGA Tour career earlier this month, with five birdies in six holes around the turn powering an opening 65.
 
“When I got here, no,” she said when asked if her score of 7-under, or even O’Donovan’s, was on her mind early Thursday.
 
“I wasn't actually feeling too great on the range, but sometimes that's good. You just lower your expectations and hit it to a foot on the first.
 
“I love playing at home. I've got all my family here and they're coming out on the weekend, so it's a bit of motivation to make the cut, so they've got something to do.
 
“I mean, last week was, elephant in the room, was a bit of a nightmare, but it was Bermuda [grass]. Coming out here on the Kikuyu, it's just quite refreshing.”
 
The unique nature of Sydney golf is something Roberts picked up during her round with O’Malley and Marcus Fraser.
 
“I was definitely watching what they were doing,” Roberts said.
 
“Some of the shots they hit, I would never have thought of ever doing. I think it was the second hole using a wood from off the grain to chip. Probably would never do that, but it was cool to watch.”
 
Playing in front of friends and family, several local players found themselves in contention early, including O’Donovan, whose score was a measure of his development.
 
“I played this event last year and I was definitely a different golfer,” O’Donovan said.
 
“I finished my round 6-over last year in the first round. Honestly, I didn't see an 8-under out there, which Josh Armstrong had last year after the first round, and I think it was a nice little wake up call to how good you have to play to compete out here.
 
“I teed it up today definitely seeing a score like that, but I'm very, very happy with how I've played.”