Brian Gay and Scott Langley shot 7-under-par rounds of 64 on the Monterey Peninsula Golf Course on Thursday to share the first round lead at the AT&T Pebble Beach Pro-Am in California.

Four-time event champion Phil Mickelson hit every fairway in posting a 6-under 66 on the Monterey course, along with Matt Every, Kevin Kisner and Australia's Jason Day. They are tied for second with South Korea's Si Woo Kim, who posted the low score on the Pebble Beach course, and Cody Gribble, the low man at Spyglass Hill on Thursday.

It marked the fourth time Mickelson has shot 65 or lower in the opening round at Pebble Beach. He went on to win the previous three times (1998, 2005, '07).

Mickelson hit every fairway for the first time since 1998, hit all but one green in regulation and needed only 32 putts to get through the round.

"I drove the ball very well today, obviously" he told the Golf Channel. "I think history was made as far as my career, I don't think I've ever done that before, certainly in competition. So that was a big milestone for me."

The players will rotate at each of the three courses through Saturday, with Sunday's final round taking place at Pebble Beach.

Mickelson, who closed with a 5-under-par 32 on the back nine, said getting off to a fast start was critical with 100 percent chance of rain in Friday's forecast and the weekend likely to be very wet as well.

"I think it's a big factor-you don't know how it's all going to play out, but I think that it's important to get off to a good start," he said. "This was a day that we had great weather, the courses were very scorable, you need to take advantage."

Gay strung together five straight birdies to close his front nine, and then had three more in his final five holes.

Langley, who started on the back nine, ripped off eight birdies in a 12-hole span from No. 12 to No. 5, but he also made two bogeys on the day.

Dustin Johnson, coming off a victory in Saudi Arabia last week and a two-time winner at Pebble Beach, is among nine players at 5 under. That includes Jordan Spieth, who is ranked 21st in the world after entering this event at No. 3 last year. Both played at Monterey on Thursday.

NOTES: The 2019 U.S. Open will be conducted at Pebble Beach for the sixth time in June. ... Korean Ho Sung Choi, whose unique "Fisherman Swing" has made him an internet sensation, shot a 1-over 72 at Pebble Beach in the 45-year-old's first round in a PGA Tour event.

--Field Level Media