Australia's Rebecca Artis carded a career-low round of 64 to take a two-shot lead at the Deutsche Bank Ladies Swiss Open in Ticino.
Artis had eight birdies and an eagle, as well as two bogeys, on an outstanding round that left her two shots clear of Florentyna Parker, and three clear of defending champion Diana Luna and Barbara Genuini, whose round of 67 was also a career low.
Artis, who picked up six shots on the last six holes to pull clear, told the Ladies European Tour website: "I just played really solid out there. I played solid the front nine and then knocked a few in close on the back nine and got the putter going.
"I've been putting well the last couple of weeks, had a couple of top 20s and stuff like that, but I've thrown in a couple of mistakes and today I was able to just play steady golf and keep the mistakes out and make some birdies."
The highlight of Artis' round was an eagle on the 15th.
"I was hitting the ball well so I was just trying to fly it at the pins really," she added.
"The greens are soft so we can really fly it at the pin. I had a good lay-up number going up the 15th so I actually holed that for eagle there and then I had a good couple of numbers coming in."
Parker was on fire over the front nine, recording five birdies, but could only manage one on the way back to settle into second place.
Still, that was one better than Luna who had six birdies but one bogey.
"It's a very nice way to start a tournament of course, especially when you are defending champion," Italian Luna said.
"You want to do well and I did so. I'm very glad and I like very much the course. It was in good shape. Considering the big amount of water over the last few days I think the course is playing great."
The 2010 winner Lee-Anne Pace was one of seven players to record a round of 68, four shots off the lead.
Scotland's Carly Booth had a hole in one, the first of her career in a tournament, on the 11th and finished with a two-under-par 70.
Collated first round scores (Par: 72)
64 Rebecca Artis (Aus)
66 Florentyna Parker (Eng)
67 Diana Luna (Ita), Barbara Genuini (Fra)
68 Stacey Keating (Aus), Ashleigh Simon (Rsa), Stefania Croce (Ita), Lee-Anne Pace (Rsa), Caroline Westrup (Swe), Virginie Lagoutte-Clement (Fra), Nontaya Srisawang (Tha)
69 Jessica Yadloczky (USA), Miriam Nagl (Ger), Rachel Bailey (Aus), Anne-Lise Caudal (Fra), Henrietta Zuel (Eng), Veronica Zorzi (Ita), Karen Lunn (Aus), Linda Wessberg (Swe), Carlota Ciganda (Spa), Marjet Van Der Graaff (Ned)
70 Laura Davies (Eng), Trish Johnson (Eng), Caroline Masson (Ger), Dawn Shockley (USA), Felicity Johnson (Eng), Lydia Hall (Wal), Caroline Rominger (Swi), Carly Booth (Sco), Rebecca Codd (Irl), Caroline Afonso (Fra), Sahra Hassan (Wal), Hannah Burke (Eng), Danielle Montgomery (Eng), Meaghan Francella (USA), Jade Schaeffer (Fra), Steffi Kirchmayr (Ger)
71 Maria Beautell (Spa), Rebecca Hudson (Eng), Cassandra Kirkland (Fra), Jenni Kuosa (Fin), Becky Brewerton (Wal), Anja Monke (Ger), Caroline Martens (Nor), Stacy Lee Bregman (Rsa), Malene Jorgensen (Den), Elisabeth Esterl (Ger)
72 Anais Maggetti (Swi), Zuzana Kamasova (Svk), Elin Emanuelsson (Swe), Melanie Maetzler (Swi), Elizabeth Bennett (Eng), Amelia Lewis (USA), Esther Choe (USA), Kylie Walker (Sco), Georgina Simpson (Eng), Kyra Van Leeuwen (Ned), Lisa Holm Sorensen (Den), Laura Cabanillas (Spa), Bree Arthur (Aus), Vikki Laing (Sco), Kiran Matharu (Eng), Marianne Skarpnord (Nor), Monique Smit (Rsa), Line Vedel (Den)
73 Titiya Plucksataporn (Tha), Giulia Sergas (Ita), Kendall Dye (USA), Tania Elosegui (Spa), Ursula Wikstrom (Fin), Mianne Bagger (Den), Adriana Zwanck (Spa), Connie Chen (Rsa), Klara Spilkova (Cze), Chrisje De Vries (Ned), Liebelei Lawrence (Lux), Eleanor Givens (Eng), Helen Alfredsson (Swe), Lynnette Brooky (Nzl), Maria Ohlsson (Swe), Joanna Klatten (Fra), Carin Koch (Swe), Lucy Williams (Eng)
74 Holly Aitchison (Eng), Mikaela Parmlid (Swe), Stefanie Michl (Aut), Nikki Garrett (Aus), Louise Stahle (Swe), Tandi Cuningham (Rsa), Yu Yang Zhang (Chn), Marieke Nivard (Ned), Beth Allen (USA), Margherita Rigon (Ita), Lucie Andre (Fra)
75 Sophie Sandolo (Ita), Lotta Wahlin (Swe), Clare Queen (Sco), Sophie Giquel-Bettan (Fra), Valeria Martinoli (Swi), Louise Larsson (Swe), Sophie Walker (Eng), Kym Larratt (Eng), Mireia Prat (Spa), Cylia Damerau (Swi), Rachel Jennings (Eng), Julie Maisongrosse (Fra)
76 Nina Holleder (Ger), Celine Palomar (Fra), Stephanie Na (Aus), Nicole Gergely (Aut), Fabienne In-Albon (Swi), Gwladys Nocera (Fra), Martina Eberl-Ellis (Ger), Florence Luscher (Swi), Elena Giraud (Fra)
77 Alexandra Vilatte (Fra), Julie Greciet (Fra), Sara Brown (USA)
78 Fanny Vuignier (Swi)
79 Carmen Alonso (Spa), Frances Bondad (Aus), Charlotte Ellis (Eng)
80 Nadine Gruter (Swi)
81 Sharmila Nicollet (Ind)
84 Sara Djos (Swe)
86 Matia Maffiuletti (Ita)