VIENNA, July 28, 2012 (AFP) - Wiesberger finished 19 under on the par-72 course at Atzenbrugg, near Vienna, three shots clear of Irishman Shane Lowry and Thomas Levet of France after sinking seven birdies in the last 10 holes -- including from a 50-foot putt on 18.
"I actually could have made birdies on the other three holes. I knew that if I could hit good shots I could get lots of birdies," the delighted 26-year-old said. "And it went perfectly."
It was Wiesberger's second European Tour title of the year following his triumph at the Ballantine's Championship in April, and he becomes the second Austrian to win his home Open after Markus Brier in 2006.
"It's the best day of my life so far," Wiesberger said. "It seems like it went my way, especially the last two holes.
"I had such a great country and such great fans backing me. I'm very proud to be following in such big footsteps (as Brier). I'm sure I'm not going to be the last home winner."
Rain drenched the opening day on Wednesday, forcing a suspension, and organisers called off play on Thursday over fears of lightning.
However, summer returned on Friday and Saturday with lots of sunshine and just a light breeze.
Olesen, who had topped the leader board on days one, two and three, saw the magic disappear in the final round, hitting a two-over 74 and bogeying three of the last five holes to finish five behind in fifth place at 14 under.
On the opening round Olesen had tied first place with Pablo Larrazabal of Spain after an eight-under 64 that equalled the course record, followed by two rounds of 68 to be three shots clear with one round to play.
Lowry shot a 66 in the final round, his lowest score of the tournament, after an eagle on the par-five six and two sets of back-to-back birdies on the back nine.
Levet, who had hit a 65 on the opening day, managed a four-under 68 after three birdies on the back nine. He was in contention until a bogey five on the 17th -- for the second day running.
Rikard Karlberg of Sweden was fourth at 15 under after a two-under 70 in the final round.
Tied in sixth place at 13 under were Scotsman Chris Doak, after a four-under final round, and Benjamin Hebert of France.
Collated final round scores in the Austrian Open on Saturday:
(Britain and Ireland unless otherwise stated)
(Par-72)
269 - Bernd Wiesberger (AUT) 71-66-67-65
272 - Shane Lowry 70-68-68-66, Thomas Levet (FRA) 65-70-69-68
273 - Rikard Karlberg (SWE) 70-67-66-70
274 - Thorbjorn Olesen (DEN) 64-68-68-74
275 - Chris Doak 73-66-68-68, Benjamin Hebert (FRA) 72-68-64-71
276 - Scott Jamieson 71-67-70-68, Richard Bland 69-67-68-72
277 - Pablo Larrazabal (ESP) 64-76-68-69, Emiliano Grillo (ARG) 70-68-69-70
278 - Chris Wood 71-69-70-68, Robert-Jan Derksen (NED) 72-68-69-69
279 - Niclas Fasth (SWE) 69-70-72-68
280 - Alastair Forsyth 68-72-72-68, David Drysdale 71-69-70-70, Oliver Wilson 68-70-68-74
281 - Tim Sluiter (NED) 76-68-73-64, Tjaart Van Der Walt (RSA) 74-69-71-67, Felipe Aguilar (CHI) 67-71-75-68, Mathias Gronberg (SWE) 70-75-67-69, Romain Wattel (FRA) 72-69-72-68, Taco Remkes (NED) 70-71-70-70, Steven O'Hara 70-70-67-73, Gregory Bourdy (FRA) 70-69-68-74