Queenslander Billy Dowling was the best of the Australians and had another assured day on his first visit to the Sandbelt, posting a two-over score of 73 to sit one-over and in outright second, four shots behind the leader.

Yet it was Sampson's day at Royal Melbourne's Goliath.

With 50km/h winds shaking the press tent and sending dusty squalls whinnying off the paths, the 22-year-old from Tianjin shot 6-under 65 and broke the record for best amateur score at Royal Melbourne's composite course, set by Sir Michael Bonnallack in 1968, and equalled on Thursday by Kiwi Kazuma Kobori.

Commentator Frank Nobilo observed that Zheng was "in a different league today", a point rammed home given the next best nine players on the leaderboard were an accumulative 31-over par.

Geoff Ogilvy said "it was the most ridiculous round I've ever heard of."

Zheng said "they were the toughest conditions I've ever played in."

"I think I got the best of the golf course today," he said. "The golf course is still a beast. I mean, the second shots are going 20-30 yards further with the wind. Even on the tee boxes, the ball was wobbling."

Yunhe 'Sampson' Zheng's 65 was one of just four scores under-par on Saturday. PHOTO: AAC.

Zheng made six birdies and an eagle, and said he didn't look at the leaderboard untll the 10th hole when he saw he was in the equal lead after beginning the the day three shots behind.

"I figured there were some shorter, opportunity holes coming in and there was no reason not to keep the gas pedal down and make some more birdies," Zheng said.

Zheng is a member of the University of California Golden Bears golf team and according to the university's website speaks three languages and enjoys reading, cooking and fishing.

Billy Dowling had another assured day around Royal Melbourne after playing his first round on a Sandbelt course earlier in the week. PHOTO: AAC.

Best of the Australians was again Gold Coast local Dowling who will play in the final group on Sunday with Zheng and Kobori whose 74 leaves him five shots behind the leader. 

Elsewhere Kingston Heath member Max Charles, who played in the same group as Zheng, shot an excellent even-par round of 71, to sit at T5 with fellow Victorian Jasper Stubbs (74).

Sydney's Jeff Guan (74) is two shots further back in T9. 

CT Lin of Chinese Taipei began the day equal leader and showed off some genuine artistry around the slick Royal Melbourne greens with a pair of sublime chips that began at right angles to the flag before feeding slowly to the hole and finishing four feet.

Unfortunately for him he missed both putts, shot 7-over 78 and ended the day 10 shots back and tied for 7th.