USA's Kent Jones carded a six-under-par 66 to take a one-shot lead after the opening round of the Pebble Beach National Pro-Am.

Jones posted four of his six birdies on the back nine to go top of the leaderboard with a bogey-free round at the 6million US dollar event.

John Mallinger, Roland Thatcher and Brad Adamonis are one shot adrift on five under, while Jay Williamson is one of 10 players tied for third at four under.

Mercedes-Benz Championship-winner Daniel Chopra headlines a group of 11 players at three under and defending champion and three-time tournament winner Phil Mickelson finished at one under.

First prize is 1.08million US dollars.