Jackson Koivun looked quite comfortable in his Presidents Cup debut. More like a seasoned veteran than the youngest player on the U.S. team. The 21-year-old Koivun defeated Si Woo Kim 2 up in singles, part of an epic rally for the Americans in a 17-13 victory over the International squad. The former Auburn star went 2-0-1 in his three matches at Medinah Country Club in suburban Chicago. U.S. captain Brandt Snedeker says Koivun is special. Koivun led the Tigers to the NCAA title in June. Almost two months later, the California native won the 3M Open in his third professional start.