Gregory Havret leads the Omega European Masters after his hole-in-one on the 13th hole in Crans saw him clear of the rest of the field, while Michael Hoey repeated the feat on the same hole.
The 38-year-old Frenchman carded an opening round of 63 to finish seven under par, also recording an eagle at the seventh before acing the par-three 13th at Crans-sur-Sierre.
A dropped shot at the 10th was the only blemish on Havret's scorecard as he targets his first European Tour win since 2008.
Havret's was not the only hole in one as Northern Ireland's Hoey later matched his effort at the same hole.
Hoey's was the 39th ace on the European Tour this season, equalling the all-time high set in 2006, and leaving him two shots off the lead on five under.
"It's a little bit strange, for a few seconds you don't know what to do because you can't believe it," Havret told europeantour.com of his hole-in-one.
"Then when you hear everybody shouting and cheering by the green, you know it's real and you start to go crazy yourself.
"After that happened, you couldn't take the smile from off my face, because I knew that whatever happened for the rest of the round, I would have a very nice prize waiting for me. So I was very happy, and I play my best golf when I'm happy."
Lasse Jensen of Denmark is just a shot further back, with Tyrrell Hatton missing out on the overnight lead after a poor final hole.
The Englishman was at eight-under par but found the water on the 18th and hit a triple bogey to leave him down in a group at five under.
Compatriots Danny Willett, Seve Benson and Richard Bland are also in that 12-man tie for third, with the former having taken an early clubhouse lead after fog held up the early starters.
Lee Westwood, also out early, finished his round two under par and tied for 39th despite a poor start.
World number 10 Sergio Garcia was a shot further back as the Spaniard, who has a property in the Crans Montana area but is appearing in the event for the first time in nine years, opened with a double bogey at the first.
Of the other Irish involved; Peter Lawrie shot a three under 67 to tie for 21st, while Damien McGrane lies on three over.
