Jackson Koivun has already arrived, but in Presidents Cup debut, he showed up

Koivun wrapped up a 2-0-1 performance at Medinah with a 2-up victory over arguably the Internationals’ biggest star, Si Woo Kim, in Sunday singles, the type of showing that U.S. captain Brandt Snedeker envisioned when he tabbed the budding superstar as one of his six captain’s pi