American Jason Kokrak leads the Northern Trust Open by one stroke after charging up the leaderboard in the second round on Friday.

Kokrak carded a near-flawless seven-under-par 64 to hit the front at the Riviera Country Club.

Still searching for his maiden win on the PGA Tour, having claimed two Nationwide titles, Kokrak had three birdies and a bogey on the front nine.

Kokrak then added another five birdies across nine faultless holes after the turn in Pacific Palisades, California.

Behind Kokrak is countryman Chez Reavie, who shot a second-round 67.

Tied for third at eight under is Dustin Johnson (66), as well as 2014 champion Bubba Watson (68) and Troy Merritt (66) as overnight leader Camilo Villegas dropped five shots behind Kokrak.

Australian Marc Leishman is in sole possession of sixth spot following his four-under-par 67.

World number three Rory McIlroy (69) and Adam Scott (68) head a group of eight players at six under through 36 holes.

Much had been made of McIlroy and world number one Jordan Spieth going head-to-head on the PGA Tour for the first time this season, but the latter will not be competing over the weekend.

After carding the worst opening round of his professional career – going eight over the card to kick-off proceedings – Spieth then missed the cut following a 68 on day two.

Spieth was five over at the end of his two rounds.

Also missing the cut was defending champion James Hahn, while Sergio Garcia, Kevin Na, Jimmy Walker, Bill Haas and Keegan Bradley failed to qualify for the final two rounds.