Bryson DeChambeau carded a seven-under-par 64 to take the lead at the halfway stage of the RBC Heritage, where Dustin Johnson showed why he is world number one.
American DeChambeau earned a one-stroke lead after 36 holes thanks to an eagle and seven birdies at Harbour Town in South Carolina on Friday.
DeChambeau dropped two shots on the front nine, having opened with an eagle at the par-five second hole, but the 24-year-old was flawless following the turn as he topped the leaderboard heading into the weekend.
Winner of last year's John Deere Classic, DeChambeau – who finished runner-up to Rory McIlroy at the Arnold Palmer Invitational – is ahead of Kim Si-woo and Ian Poulter.
Kim posted a second-round 65 to climb eight positions alongside Poulter, who recorded a 64 to be within striking distance of DeChambeau.
Overnight leader Rory Sabbatini dropped to fourth following his 70, while Brandt Snedeker (64), Chesson Hadley (68) and Luke List (64) are also two shots off the pace.
American star Johnson failed to make up any ground on Friday after carding back-to-back 69s to leave him four under overall.
Johnson, though, produced a moment of magic with an unconventional par – which saw the 2016 U.S. Open champion hampered by a green-side tree on the par-three seventh hole.
However, Johnson – despite playing off his weaker side – hit a superb chip to knock the ball within two feet before putting for par.
Defending champion Wesley Bryan, meanwhile, shot a 71 to be two under and eight strokes behind DeChambeau entering round three.
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