PGA Tour rookie Andrew Loupe produced a bogey-free round to claim a two-shot lead before play was brought to an end on day one of the AT&T Pebble Beach National Pro-Am.
Heavy rain delayed Loupe's tee-time by three hours but the 25-year-old, who has missed the cut in each of his five starts this season, managed to battle the conditions to post an eight-under round of 63.
Stuart Appleby, Jim Renner, Richard Lee and Scott Gardiner are all two shots behind the leader following impressive rounds on a difficult opening day.
Phil Mickelson, who has won the tournament on five occasions, was on five-under through 15 holes before being forced to abandon play for the day due to bad light.