Martin Laird earned a narrow one-point lead at the Barracuda Championship on Thursday, scoring a round-high 15 points at Montreux.
The tournament, famed for its use of the Modified Stableford scoring system, got off to an exciting start with just five points separating Laird in first from Hunter Stewart and Tyler Aldridge in equal 12th.
With points given for double eagles (eight), eagles (five) and birdies (two) and points subtracted for bogey (minus one) and double bogeys or more (minus three) there is not much separating the field after the first round.
A total of eight birdies and a bogey made for a fine day's work for Laird, with the 14th the only hole to give him any real trouble.
Australian Greg Chalmers is in second place, after a mixed day.
Chalmers bogeyed his second hole, before a birdie and eagle got his tally back into the positives.
He would bogey his fifth hole but recovered well from there, finishing the day on 14 points.
He is joined in second place by Camilo Villegas and Gary Woodland, the former going bogey free, while the latter managed an eagle but also had three bogeys.
Col Knost, Zac Blair, Brendan Steele and Jay McLuen are in a four-way tie for fifth place on 13 points.
Defending champion J.J. Henry, meanwhile, is minus two.