Victorian Steven Jones (31) carded a smooth 6-under-par 66 at The Hills yesterday to hold a one-shot lead over fellow Australian Callan O'Reilly.
Australians have won the Open the past four years, and already occupy six of the top eight spots on the leader board.
Jones' first round, which was mostly played in wind and rain, was made more impressive by the fact it is only his seventh tournament since taking last year off to look after his wife Kate, who had a brain tumour.
"She's doing really well now, so I'm able to play,'' Jones said.
"But last year was a little tough. Mentally, it was hard to juggle the rigours of professional golf and travelling and being the person I needed to be at home.
"I wasn't sure when I was going to be able to play again. I actually didn't miss playing for a long time, because the year before it was so stressful with what I was going through off the course and playing really inconsistently.''
Jones, who started his round from the 10th hole, made a scratchy start to the day after bogeying the first two holes.
But he bounced back to birdie five of the next eight holes, including a lovely chip in from the edge of the green on the 12th.
"By that stage, I was feeling pretty good about my golf,'' he said.
"My putting was good and I was hitting some nice iron shots. I had a little bit of luck on the way; it was good.''
Jones' only blemish down the stretch was on the par-3 fourth hole, which he bogeyed. He then rattled off three birdies and a couple of pars to complete a fine round, which sets him up nicely for his round on Millbrook today.
Palmerston North's Joshua Munn is flying the New Zealand flag.
He is tied for third after firing a 4-under-par 67 at Millbrook, a round which started with his chipping in for a lovely eagle on the first hole.
Munn (25), who only turned professional a month, was 5-under heading into the 18th, but dropped a shot after finishing with a bogey.
His tee shot flared right and out of bounds, before he hit his re-take on to the green and finished with two putts.
"I was trying to stay aggressive,'' he said.
"It is what it is; you can't take anything back now. Like I said, I kept the aggressive mindset and I was trying to finish at 6-under instead of 4-under.''
With rain, wind, lightning and thunder making life tough for players for the first couple of hours, favourite Ryan Fox said he was relieved to come away with a 3-under 69 round at Millbrook.
"It was certainly one of those days you could play your way out of the tournament. It was probably one of the strangest days I think I've ever had on the golf course in terms of weather, I've never really seen anything like that.''
Fox, who is tied for 10th, carded four birdies and two bogeys at Millbrook, a course on which he tends to "struggle'' to read the greens.
His round included a shot which started fading towards the boundary, only for a gust of wind to blow it back in to play and into the rough.
"I don't think I've ever seen a brand new golf ball do that,'' Fox said.
"And then you see the trees halfway down the hole blowing hard left to right and the trees behind the green blowing hard right to left.
"My caddie goes to me, ‘Just don't ask me, I don't have a clue, I'm just guessing like you are,'.''
Fox will play The Hills today, his more favoured course, hoping to post a low score to remain in contention for the weekend.
After wind stuck around all day and even blew balls off the green yesterday, better weather is forecast for the final three days.
● Australia leads New Zealand 3-1 after the first round of the celebrity challenge. Shane Cortese picked up New Zealand's only win, against former Australian captain Allan Border, but Stephen Fleming, Justin Marshall and Brendon McCullum lost to Glenn Robbins, Ricky Ponting and Ivan Cleary respectively.
