Graeme McDowell sits three shots off the lead after the opening round of the AT&T Pebble Beach Pro-Am in California.
A poor three-putt bogey from 21 feet at the 18th took some of the gloss off his day but he was still just three shots behind early leader Brian Gay, who shot a seven-under 64 at Monterey Peninsula where four-time victor Phil Mickelson carded a 65 and Dustin Johnson and Jordan Spieth opened with 66s.
Mickelson, who was runner-up to Adam Long at last month's Desert Classic but missed the cut at the Phoenix Open last week, hit all 13 fairways for the first time in a PGA Tour round since the Farmers Insurance Open in 1998.
"I'm not going to chase them as hard as past year because you can get hurt doing that, you can get into some bad patterns".
"I don't think I've ever done that before, certainly in competition, so that was a big milestone for me. This was a day we had great weather, courses were very "scoreable", so you needed to take advantage of that".
The pros also have a traditional stroke-play tournament over the four days on California's Monterey Peninsula.
While he failed to get up and down from sand and dropped shots at the par-three fifth and 12th holes, his iron play was superb and his putting clinical as he made birdies at the second, fourth, sixth, ninth, 11th, 13th and 15th.
Langley, who is yet to claim a win on the Tour, reeled off nine birdies and two bogeys on the Monterey course on his way to a share of the lead.
"I've just got a clearer head", the former world No.1 said.
Johnson said last week's victory at the Saudi International on the European Tour was important.
Choi, who has won twice on the highly-regarded Japan Tour including the Casio World Open late previous year, had never been to the United States before arriving in California this week.
NOTES: The 2019 U.S. Open will be conducted at Pebble Beach for the sixth time in June.
Ho Sung Choi, the South Korean who has become a video sensation with the gyrations he makes after his swing, played alongside Green Bay Packers quarterback Aaron Rodgers, who greeted him with "hello" in Korean.