(San Francisco, CA)  --  Jason Day and Brendan Todd are atop of the leaderboard at the PGA Championship in San Francisco.  Both shot a five-under 65 in Thursday's first round at TPC Harding Park to lead by one stroke.  Nine players are tied for third at four-under, including Brooks Koepka. Tiger Woods shot a two-under 68 and sits three strokes off the lead.