(San Francisco, CA)  --  Collin Morikawa fired a six-under 64 in the final round to win the PGA Championship at TPC Harding Park in San Francisco.  The 23-year-old California native is the first player to win the PGA in his first appearance since 2011.  He finished 13-under, two strokes ahead of third-round leader Dustin Johnson and Paul Casey.  Brooks Koepka, who won the past two PGA Championships, faded from contention with a final-round 74.  Tiger Woods tied for 37th at one-under par, 12 strokes behind Morikawa.