CASTLE ROCK, Colo., Aug. 10 (UPI) -- With 13 points on Thursday, Mathias Gronberg has a 2-point lead after the opening round of the PGA's International at Castle Rock, Colo.
The event uses a modified Stableford scoring system, with eight points given for double-eagles, five for eagles and two for birdies, while one point is subtracted for bogeys and three points for double-bogeys or worse.
The 36-year-old Gronberg made a double-bogey on the par-4 ninth hole for his lone blunder of the day. Eight birdies more than made up for that.
"I found my game on the driving range yesterday," said Gronberg, a native of Sweden, who knows his chances of earning a spot on the European Ryder Cup team are slim.
Danny Ellis, Jeff Brehaut and Patrick Sheehan are tied for sixth with 10 points.