Geelong - Spain's Alejandro Canizares blitzed a nine-under-par 63 to top the leaderboard among the men on Thursday while in-form Swede Madelene Sagstrom shared the women's spoils at an innovative tournament in Australia.
The Vic Open is the only event in the world with male and female fields teeing off, in alternate groups, on the same course and for equal prize money.
It has been running as a dual event for seven years.
But the tournament took on added significance last year with the European Tour and the US-based LPGA Tour jointly sanctioning it for the first time, with prize money significantly boosted.
Played at the 13th Beach Golf Links south of Melbourne, Canizares fired 10 birdies to one bogey in his 63 to be two ahead of a chasing pack of four Australians -- Matt Griffin, Travis Smyth, Jake McLeod and Justin Warren.
"I putted really well. It was one of those days where you saw the hole pretty big," said Canizares.
Sagstrom shares top spot in the women's field after a 65, matching South Korea's Kang Haeji and Taiwan's Peiyun Chien.
The Swede, who claimed her first LPGA win two weeks ago in the United States, started with six birdies in her first seven holes before breaking a run of pars with birdies at each of the last three.
"I think after my first win it definitely added confidence to everything, just knowing that I can compete out here, knowing that I can win on tour," she said.
Incredibly, two strokes behind is English veteran Laura Davis, who has been on tour for 35 years but was playing her first event in six months after taking time off to look after her ailing mother.
"That's the best I've putted in 20 years," said the 56-year-old, who has 87 worldwide victories to her name. "I don't know how many putts I had, but it wasn't many.
"This might even be my favourite tournament," she added.
To accommodate the dual fields, there are two cuts - one as usual after round two, and another reducing the men's and women's fields to 35 players after 54 holes.
Leading scores on Thursday on day one of the joint European Tour and LPGA Tour-sanctioned Vic Open in Geelong, where the men's and women's tournaments are played side-by-side (par-72; AUS unless stated):
63 - Alejandro Canizares (ESP)
65 - Matthew Griffin, Travis Smyth, Justin Warren, Jake McLeod
66 - Brad Kennedy, Robin Sciot-Siegrist (FRA), Aaron Cockerill (CAN), Andrew Evans, Min Woo Lee, Andrew Martin, Jediah Morgan, Zach Murray
67 - Derek Ackerman (USA), Wil Besseling (NED), Jonathan Caldwell (NIR), Jarryd Felton, Nick Flanagan, Ryan Fox (NZL), Simon Hawkes, Michael Hendry (NZL), Steven Jeffress, Shae Wools-Cobb, Gareth Paddison (NZL), Sean Crocker (USA), Geoff Ogilvy, Ashley Hall, Matthew Stieger, Peter Wilson
65 - Kang Haeji (KOR), Madelene Sagstrom (SWE), Chien Peiyun (TPE)
66 - Haley Moore (USA), Linnea Strom (SWE)
67 - Dana Finkelstein (USA), Stephanie Meadow (NIR), Laura Davies (ENG), Lin Xiyu (CHN), Tiffany Joh (USA), Christina Kim (USA), Cheyenne Knight (USA), Pornanong Phatlum (THA), Pavarisa Yoktuan (THA), Klara Spilkova (CZE)
68 - Cydney Clanton (USA), Ally McDonald (USA), Park Hee-young (KOR), Alena Sharp (CAN), Tsai Pei-ying (TPE), Matilda Castren (FIN), Lee6 Jeongeun (KOR), Stephanie Kyriacou