Dustin Johnson laid down a daunting marker for the rest of the field as he soared into a three-stroke lead at the Saudi International powered by SBIA.
The World Number Three produced a flawless second round of nine under par after taking advantage of calmer conditions on Friday morning to move ahead at the Royal Greens Golf & Country Club.
Johnson rolled in seven birdies and a terrific eagle to get to 11 under for the tournament, with Zander Lombard three shots adrift alongside China’s Li Haotong.
The South African could have closed the gap on the 2016 US Open Championship winner, but the Q School graduate bogeyed the last to see him drop to eight under, while Li carded six birdies and a solitary bogey to join Lombard in tied second.
Overnight leader Thomas Pieters, who has yet to get his second round under way, was in tied fourth with Paraguay’s Fabrizio Zanotti at seven under, while Frenchman Alexander Levy and South Africa's Richard Sterne were one shot further back.
Last week's Omega Dubai Desert Classic winner Bryson DeChambeau is at four under after a second successive 68 by the World Number Five.
Johnson, starting on the back nine, began his assault to the top of the leaderboard with back-to-back birdies at the tenth and 11th to move to four under.
The American improved his score with a gain at the 15th and 18th to get to six under, but he was still three adrift of leader Lombard following his stunning form around the turn.
Lombard, who also started on the back nine, bogeyed the 12th before turning it around with a birdie-eagle from the 17th to sit alongside Pieters as joint leader.
A close chip to concessional range at the first put the South African into the outright lead and when he dialled in to six feet at the next, he was two ahead.
However, Lombard carded a bogey at the last to drop to eight under, while Johnson moved one behind with a 20-foot birdie putt at the second.
The 34 year old then took the lead for the first time with a superb eagle at the fourth when he rolled in a 30-foot putt from the fringe.
But he did not stop there as he holed out successive birdies from the sixth to take a stranglehold at the top in King Abdullah Economic City.
Li hit birdies at the 11th and 13th to start his round in positive fashion and moved to seven under when he rolled in great long putts from 25 feet and 35 feet respectively at the second and third.
His progress stalled when he got onto the par-five fourth in three shots, but three-putted for his only blot on this card, only to hit back with birdies at the seventh and the ninth.
Levy mixed an eagle, five birdies and two bogeys for a five-under-par 65 in his second round to get to six under.
Twelve-time European Tour winner Ian Poulter moved into contention at five under alongside South Africa Justin Harding, English duo Ross Fisher and Alfie Plant and Australia’s Jake McLeod.
