To answer your first question: nope, it won't take an extra full round of 18 holes. Instead: Two holes will be played and total strokes will decide the winner. If there's still a tie? It goes to sudden death until a winner gets decided.

Not since 2008, when Tiger Woods outlasted Rocco Mediate in overtime at Torrey Pines, has the U.S. Open needed more than 72 holes to decide a champion. The 17-year gap is the longest period in U.S. Open history in which a playoff has not been needed to determine a champion.