Viktor Hovland finished strongly to claim a one-stroke advantage at the halfway stage of the Farmers Insurance Open, where Brooks Koepka and Jordan Spieth missed the cut.
Hovland birdied his final hole in Friday's second round to card a seven-under-par 65 and top the leaderboard heading into the weekend at Torrey Pines.
Battling rain, hail and wind – which halted proceedings in the second round – Norwegian golfer Hovland managed to rise 47 positions to lead a star-studded field thanks to eight birdies and just one bogey on the South Course.
The 23-year-old – winner of the Puerto Rico Open and Mayakoba Golf Classic on the PGA Tour last year – is nine under through 36 holes, ahead of 2017 champion Jon Rahm (67), Adam Scott (69), Tony Finau (67), Lanto Griffin (70), Ryan Palmer (70) and Patrick Reed (72).
Alex Noren (74), who was tied for the overnight lead alongside Reed, fell into a share of 11th, three shots off the pace.
Four-time major champion Rory McIlroy is a stroke further back following his one-under-par 71 on the North Course.
McIlroy mixed four birdies with three bogeys to be tied for 14th position along with Will Zalatoris (71), Jason Kokrak (69), Adam Hadwin (70), Rory Sabbatini (67), two-time winner Brandt Snedeker (70) and Max Homa (68).
Defending champion Marc Leishman posted a second-round 70 to be three under overall, two strokes better off than rallying veteran Phil Mickelson (72).
Mickelson was on the cusp of missing the cut during the rain delay, but the five-time major champion holed back-to-back birdies to qualify for the weekend.
Former world number one Spieth (75) missed the cut as his bid to win for the first time since 2017 continues.
Koepka's 76 saw the four-time major winner also miss the cut, along with two-time Farmers Insurance Open champion Jason Day (72).