Levin and Stanley are both looking for their first PGA Tour victories. Both also played the easier North Course at Torrey Pines on Thursday and will rotate to the harder South Course on Friday. The South Course will also host the final two rounds.
Despite a double-bogey on his 14th hole, reigning FedExCup champion Bill Haas carded a nine-under 63 on the North Course and is alone in third.
Only six of the top-35 players on the leaderboard played the South Course on Friday. The leader of that group is Marc Turnesa, who carded a six-under 66 and is tied for 13th.
Among those that struggled on the South Course were Phil Mickelson and J.B. Holmes. Mickelson, who shared 49th at the Humana Challenge last week, faltered to a five-over 77 and tied for the most bogeys (seven) in the first round.
Holmes is competing for the first time since brain surgery last year. He had four bogeys in a round of four-over 76.
Levin started with a birdie on the first, but his next birdie didn't come until the par-four seventh. After a par at the eighth, he birdied eight of the last 10 holes.
He birdied the ninth and followed with a 15-foot birdie putt on No. 10. The 27-year-old dropped his approach within four feet at the 11th. After knocking that in, he got up and down for par on the par-three 12th.
Levin caught fire from there, At the 13th, he left himself three feet for birdie. On each of the next three holes, he made birdie putts of eight feet on each hole to grab a share of the lead at minus-nine.
Levin, a three-time winner on the Canadian Tour, two-putted for birdie at the last to finish at 10-under.
"It feels great. I drove the ball well today. The first couple weeks I played decent," said Levin, who tied for 23rd and 64th in his first two starts. "In those two tournaments, I didn't drive it particularly good. I drove it well today and kind of set me up because I've been putting pretty good. I had some putts for birdies instead of pars today and kind of added up to a good score."
Stanley did his scoring in bunches. He birdied the first, then parred No. 2. He poured in three consecutive birdie efforts from the third to move to four- under.
After five straight pars, Stanley tripped to a bogey on the 11th. The 24-year- old ran off four birdies in a row from the 12th to jump to minus-seven.
Stanley birdied the 17th to move within two of Levin. He erased that deficit and grabbed a piece of the lead with a three-foot eagle putt at the 18th.
"It was good. I know it was a 62, but it was a pretty boring round of golf," said an understated Stanley. "Hit a lot of greens and made a lot of putts."
NOTES: Defending champion Bubba Watson posted a three-under 69 on the North Course and is tied for 37th...Dustin Johnson, who withdrew last week with a sore back and is still recovering from offseason knee surgery, fired a six- under 66 on the North Course and is tied for 13th...The North Course played to an average of 69.244, while the South Course played to an average of 72.846...The last first-time winner of this event was Jay Don Blake in 1991.