SEOUL, April 27, 2012 (AFP) - The 26-year-old world number 170 recorded seven birdies and not a single bogey to card a seven-under par total at the halfway stage of the tournament, one ahead of Marcus Fraser of Australia.
"You know I got the odd break on the back nine," Wiesberger admitted.
"I holed a long putt on five (his 14th hole as he started on the 10th) and a chip-in at the last, which, you know, is a bonus. But some of these days it all comes together and it was one of them today."
Fraser is bidding to become the first double winner of this championship, which is celebrating its fifth anniversary this year, having won the title in 2010 when it was played on Jeju Island.
The 33 year-old Australian carded a five-under par 67 to move to six-under at the halfway stage, one ahead of Sweden's Oscar Floren.
But lurking within a few shots of the clubhouse lead and well placed for a weekend assault on the title is seasoned European Tour player Miguel Angel Jimenez of Spain, the runner-up here last year. He stands at four-under par after a 68.
Just two shots further back are English duo Paul Casey and Ian Poulter who are both on two-under after a 72 and 67 respectively.
"Obviously yesterday was very windy, pretty tricky for everybody," said Fraser, the two-time European Tour winner who is in good form having finished sixth in the Volvo China Open last week.
"And then today was completely different. We basically had no wind for most of the day and then it kicked up a little bit over the last maybe five, six holes.
"But overall, I'm very happy and very pleased with the way it's going at the moment."
Asked what it was about the Ballantine's Championship that brought the best out of him, Fraser joked: "It's obviously just the alcohol -- I can't really survive without it."
Jimenez feels he has put himself in with a great chance of going one better than last year following a four-under par 68 Friday morning and believes the leaders will be looking over their shoulders at the chasing pack.
"A couple of shots behind at the moment, you never know what's going to happen," Jimenez said.
"Well I feel nice, I feel calm and I feel peace and they (the leaders) don't feel very good because they can feel my breath on their necks," he laughed.
Floren was level par for his round and the tournament with five holes to play, but in a remarkable finish shot birdies at the 14th, 16th and 17th and capped it in tremendous style with an eagle three at the 18th.
England's Anthony Wall and Chile's Felipe Aguilar were also in the clubhouse on four-under after the conclusion of the morning rounds.
Leading second-round scores on Friday in The Ballantine's Championship, Blackstone Golf Club, Icheon, South Korea:
(Par-72, 7,302 yards)
137 Bernd Wiesberger (AUT) 72-65
138 Marcus Fraser (AUS) 71-67
139 Oscar Floren (SWE) 72-67
140 Miguel Angel Jimenez (ESP) 72-68, Anthony Wall (ENG) 73-67, Felipe Aguilar (CHI) 71-69
141 Graeme Storm (ENG) 72-69, Alexander Noren (SWE) 75-66, Oliver Fisher (ENG) 71-70, Jung Ji-ho (KOR) 70-71
142 Paul Casey (ENG) 70-72, Thongchai Jaidee (THA) 71-71, David Howell (ENG) 73-69, Ian Poulter (ENG) 75-67, George Coetzee (RSA) 71-71, Richie Ramsay (SCO) 70-72, Jamie Donaldson (WAL) 70-72, Danny Willett (ENG) 75-67
143 Ross Fisher (ENG) 71-72, Victor Dubuisson (FRA) 68-75, David Oh (USA) 73-70, Bae Sang-moon (KOR) 75-68, Choi Ho-sung (KOR) 73-70, Thaworn Wiratchant (THA) 73-70, James Morrison (ENG) 74-69, Soren Kjeldsen (DEN) 74-69, Digvijay Singh 73-70, Brett Rumford (AUS) 73-70
144 Shane Lowry (IRL) 74-70, Siddikur Rahman (BAN) 75-69, Mikko Ilonen (FIN) 75-69, Prom Meesawat (THA) 72-72, Lee Tae-kyu (KOR) 71-73, Scott Jamieson (SCO) 76-68, Paul McGinley (IRL) 71-73, Anirban Lahiri (IND) 71-73, Damien McGrane (IRL) 73-71
Selected others: 145 Y.E. Yang (KOR) 74-71
147 Adam Scott (AUS) 71-76
148 K.T. Kim (KOR) 73-75
149 Darren Clarke (NIR) 77-72