The Scot produced an eagle on the last after home favorite Ormsby's double-bogey on the 17thISPS Handa Vic Open Men's Last Leaderboard-18 D Law (Sco); -17 B Kennedy (Aus), W Ormsby (Aus); -16 J Harding (SA); -15 J Scrivener (Aus), D Drysdale (Sco), D Brandson (Aus) Other selected: -13 C Shinkwin (N), N Flanagan (Aus); -10 M Stieger (Aus), P Dunne (Ire), M Hoey (NI), A Rai (NL) ISPS Handa Vic Open female end leaderboard-8 C Boutier (Fra); -6 S Oh (Aus), C Thomas (Eng), S Kemp (Aus); -5 H Nomura (Jap), A Munoz (Spa), K Kirk (Aus) Other selected: -4 J Ewart Shadoff (Eng), K Kaufman (USA), L Stephenson (USA); -1 F Johnson
Scottish David Law eagled the 18th when he conquered a three-shot deficit in the last three holes and won the ISPS Handa Vic Open – a first European Tour title
birdied the 16th and sank an eight-foot putt on the par-five last to card a six-under 66 and win on 18 below.
Overnight leader Wade Ormsby double-bogey the 17th and missed an eagle putt on the 18th to force a playoff.
Celine Boutier from France won the women's event by two shots of three players including Charlotte Thomas from England.
The tournament is co-approved by the European Tour and LPGA and includes men and women playing on the same courts at the same time, for the same prize money.
Boutier scored a final-round 72 to keep the Australians Sarah Kemp (65) and Su Oh (74), while Thomas closed with a 69 and night leader Kim Kaufman dropped to a 78 to end four shots adrift.
the men's event, the Australian Ormsby, 38, seemed to cruise to victory but crumbled on the par-three 17th and made five shots.
Challenge Tour graduate rights, who retrieved a winner's pay of £ 820,000 said: "To win, things change a bit.
" It's huge. It is not something that I expected. For me, playing alone on the European Tour was enough.
"I loved the four events I've played so far and just being a European Tour player was what I was happy with, I go home, reflect a bit on things and reevaluate.
"We said we would try to finish three-two-four in the hope that we would get a top-three finish. When bird 16, par 17, and the last time descended, we said that we need an eagle. We make an eagle, we put 18 under it, you never know what can happen. "
Brad Kennedy finished at the age of 17 next to Ormsby, one shot away from Justin Harding from South Africa, Scotland David Drysdale and Australian duo Jason Scrivener and David Bransdon made a shot further back.