Graeme McDowell slipped back with a second round 72 on what was a considerably easier day for scoring at the CJ Cup at Nine Bridges in South Korea.
The Northern Irishman made three bogeys on his front nine but tempered those with three birdies to sign for a level par round and head into the weekend at one under par, eight shots off the lead held by American Scott Piercy.
Scott Piercy holds a one-shot lead after the second round with Brooks Koepka in second place as he chases the world number one ranking.
Three-time major winner Koepka can reach top spot in the rankings for the first time with victory. A solo second-place finish would also be enough assuming current world number four Justin Thomas doesn’t win the event.
American Piercy picked up four birdies on the front nine as he shot a 65 to sit nine under, one stroke ahead of compatriot Koepka in the $7.2million (€6.3million) event.
An eagle three at the 18th helped Koepka also sign for a seven-under round — which could have been better but for a bogey at the par-five ninth.
Defending champion Thomas, knowing a win would lift him back to world number one, improved slightly after his opening 73 to move to one under after a second round of 70 — but sits eight shots off the lead.
Ian Poulter, who helped drive Europe to Ryder Cup success, is in fourth place after his 69.
The Englishman had struggled early on after dropping two shots in the opening three holes before recovering them to head into the turn at even par for the day.
Further birdies on the 12th, 14th and at the par-five last helped keep Poulter right in contention heading into the weekend.
Sweden’s Alex Noren raced up the leaderboard with another blemish-free seven-under round to also sit at five under.
Overnight leader Chez Reavie dropped back to third after his 70, with successive bogeys over the closing holes proving costly.
Friday’s best round came from Brian Harman, the American producing a strong finish with four straight birdies to sign for a 64 and climb up to a tie for sixth place, some five shots off the lead.
England’s Paul Casey hit a hole-in-one at the par three seventh, but then sank four bogeys in his 73 to drop down to tied for 30th.
Former Masters champion Danny Willett had been just a shot off the lead at the start of the day. However, a five-over 77 — which included a double-bogey at the fifth — saw him fall out of contention.
Collated second round scores & totals in the USPGA Tour The CJ Cup at Nine Bridges, Nine Bridges Country Club, Jeju Island, South Korea (USA unless stated, irish in bold, par 72):
135 Scott Piercy 70 65
136 Brooks Koepka 71 65
138 Chez Reavie 68 70
139 Alex Noren (Swe) 74 65, Ian Poulter (Eng) 70 69
140 Pat Perez 72 68, Gary Woodland 73 67, Ryan Armour 73 67, Brian Harman 76 64, Jamie Lovemark 72 68
141 Cameron Smith (Aus) 74 67, Andrew Putnam 73 68, Jimmy Walker 72 69, J.J. Spaun 71 70
142 Kevin Na 73 69, Joel Dahmen 72 70, Ryan Palmer 72 70, Sung Kang (Kor) 75 67, Adam Hadwin (Can) 71 71, Brice Garnett 73 69, Si Woo Kim (Kor) 69 73
143 J.B. Holmes 73 70, Justin Thomas 73 70, Tae hee Lee (Kor) 72 71, Graeme McDowell (NIrl) 71 72, Rod Pampling (Aus) 70 73, Patton Kizzire 71 72, Louis Oosthuizen (Rsa) 72 71, Rafael Cabrera-Bello (Spa) 73 70
144 Nick Watney 70 74, Jason Day (Aus) 73 71, Kyle Stanley 72 72, Adam Scott (Aus) 75 69, Jason Dufner 72 72, Brian Gay 74 70, Peter Uihlein 73 71, Ted Potter, Jr. 77 67, Dong-Seop Maeng (Kor) 71 73, Ernie Els (Rsa) 73 71, Paul Casey (Eng) 71 73, Keith Mitchell 75 69, Brandt Snedeker 72 72, Sungjae Imn (Kor) 73 71
145 Brian Stuard 77 68, Hideki Matsuyama (Jpn) 71 74, Austin Cook 70 75, Beau Hossler 75 70, Brendan Steele 74 71, Joaquin Niemann (Chi) 75 70 ,James Hahn 76 69, Tyrrell Hatton (Eng) 72 73, Cheng-Tsung Pan (Tai) 76 69, Michael Kim 70 75, Kevin Tway 73 72, Ryan Moore 72 73
146 Hyungjoon Lee (Kor) 74 72, Abraham Ancer (Mex) 75 71, Charl Schwartzel (Rsa) 76 70, Marc Leishman (Aus) 75 71, Stewart Cink 77 69, Danny Willett (Eng) 69 77
147 Charley Hoffman 76 71, Byeong-Hun An (Kor) 70 77 Kevin Chappell 76 71
148 Emiliano Grillo (Arg) 73 75, Sang Hyun Park (Kor) 75 73, Branden Grace (Rsa) 75 73, Billy Horschel 74 74, Chesson Hadley 75 73, Charles Howell III 72 76
149 Shubhankar Sharma (Ind) 74 75, Xander Schauffele 76 73
150 Jason Kokrak 77 73
151 Whee Kim (Kor) 76 75, Kyoung-hoon Lee (Kor) 78 73
152 Doyeob Mun (Kor) 72 80
153 Hyun-woo Ryu (Kor) 77 76
154 Min Chel Choi (Kor) 82 72
