MELBOURNE, Australia (AFP) — Lucas Herbert surged into a four-stroke lead at the Australian Open in Melbourne on Friday as his LIV Golf teammate Cameron Smith imploded on the back nine.

In the women’s event, South Korean teenager Yang Hyo-jin upstaged a slew of big guns to be a shot clear after a 71 left her nine-under for the tournament.

The 17-year-old’s mettle will be tested over the weekend with major winners Shin Jiyai of South Korea, Australia’s Hannah Green, and South Africa’s Ashleigh Buhai all lurking.

Shin is shot back alongside Australia’s Justice Bosio with Green one further adrift. Two-time defending champion Buhai is tied for fifth, five off the pace.

The mixed Australian Open involves men and women teeing off in alternating groups on the same courses.

Kingston Heath in Melbourne’s famous sandbelt region is the main venue across all four days while Victoria Golf Club also hosted play on the opening two days.

Overnight leader Herbert opened with an eagle and two birdies and while a bogey at the 10th proved a setback, he responded with three more birdies in a 66 to be 14-under.

It gave him a solid cushion at the second event of the DP World Tour’s 2025 season ahead of American Ryggs Johnston, who poured in five straight birdies in his 68 to be outright second.

A group of six are a shot further back, including Australian Elvis Smylie who won his maiden DP World Tour title at the Australian PGA Championship last week.

“I’ll be in the last group, which is where I wanted to be coming into the weekend,” Herbert, a three-time winner on the European circuit, told reporters.

“But I’ve got 36 holes on the sandbelt (left). I’ve played a lot of golf at Kingston Heath. I think the easiest trap to fall into would be thinking you’ve got control of this golf tournament.”

While Herbert coped when the wind got up, Smith struggled.

The 2022 British Open champion, who was two behind after round one, opened with an eagle then sank three birdies on the front nine.

But as it got gusty his game deserted him with three bogeys and a double bogey ruining his card, leaving him eight adrift.

“Made some really poor choices mentally, I think, and led to a few bogeys,” Smith said.

“You kind of get on that train in that wind and it’s not a good spot to be in.”