Argentine Andres Romero tops the leaderboard at the Reno-Tahoe Open after scoring 14 points in the opening round of the stableford event, with Stuart Appleby leading the Australian challenge.
In the first PGA Tour competition to use a modified stableford system since 2006, players at the Reno-Tahoe are awarded two points for a birdie and five for an eagle, but can also lose one point if they bogey a hole and are docked three points for a double bogey or worse.
Romero, the 2008 PGA Tour Rookie of the Year, negotiated the front nine at Montreux Golf and Country Club with ease, sinking back-to-back birdies at two and three and again at five and six, before holing another birdie at nine to reach the turn with 10 points.
The back nine proved less fruitful but still productive, with birdies at 13 and 18, along with seven pars, completing a bogey-free round for the 31-year-old in Nevada that saw him finish with 14 points.
Appleby ended Thursday's opening round tied 15th with eight points, after recovering from a mixed start.
Teeing off on the back nine, the 41-year-old sank birdies at 13 and 18, but also had a bogey at 12 and a double-bogey at the par-three 16th.
He rallied to sink three successive birdies between two and four, adding another birdie for good measure at the par-three seventh.
Appleby's compatriot Nick O'Hern is tied 22nd on seven points, but they were the only two success stories for Australia on Thursday.
Five other Aussies in the field are all in danger of missing the cut, while Matt Jones was disqualified.
Gavin Coles (two points) in a tie for 80th has the best chance of survival, while Steven Bowditch (one), Rod Pampling (zero), Matthew Goggin and Nathan Green (both negative one) look to be heading home early.
At the other end of the leaderboard, South Korean Noh Seung-Yul finished the day outright second, one point behind Romero after carding seven birdies and one bogey.
Romero and Noh are followed by a three-way tie for third, with Americans Josh Teater, John Mallinger and Ricky Barnes all registering 11 points.
And another all-American group are a further point back in a share of sixth, with Hunter Haas, JJ Henry, Patrick Cantlay and colourful veteran John Daly level on 10 points.