Rickie Fowler has shot a rollercoaster two-under-par 68 to take the lead at the midway point of the US Open at 10 under while tying the championship's 36-hole record of 130.
Fowler needed to birdie the par-4 18th hole at Los Angeles Country Club to break the 36-hole score set by Martin Kaymer at Pinehurst No.2 in 2014.
He settled for a two-putt par, one of only four he made in a second round that also included eight birdies and six bogeys.
After opening with three straight birdies, he became the fastest player in history to reach 11 under at a US Open.
The 34-year-old Fowler, from Murrieta about 160 kilometres south of Los Angeles, is trying to win his first major.
He leads Wyndham Clark by one stroke, with Rory McIlroy and Xander Shauffele tied for third another shot back.
Fowler - who failed to qualify for the two previous US Opens - and Schauffele each shot tournament-record 62s in the opening round.
Leading after two rounds, Fowler was humble about holding top spot.
"I sure hope everyone can relate to struggles, because everyone deals with them," he said.
"No one's perfect. You'd be lying if you said you haven't been through a tough time, especially if you play golf.
"It's been a while since I've felt this good in a tournament, let alone a major.
"It's going to be a challenge, but I'm definitely looking forward to it."
Fowler was also philosophical about his up-and-down round on Friday.
"The birdies are out there if you put yourself in the right position," he said.
"But as you can see, bogeys are very easy to make."
McIlroy, who recovered from a two-over back nine, has finished in the top 10 at five of the past six majors as he tries to vanquish a nine-year major title drought.
"I started thinking about winning this thing when I came here on Monday," he admitted.
"No one wants me to win another major more than I do."
Australia's Min Woo Lee had the lowest round of the day to move to six under.
With the 24-year-old Australian's sister Minjee two shots off the lead at the halfway mark of the LPGA Classic in Michigan, it could be a memorable weekend for the Lee family.
He is tied for sixth with former world No.1 Dustin Johnson, who rebounded from a quadruple-bogey eight at the second to card an even-par 70.
World No.1 Scottie Scheffler and former amateur star Sam Bennett are tied for eighth at five under following rounds of 68.
World No.9 Cameron Smith (67) is outright 10th at four under, but the other five Australians - Lucas Herbert, Cam Davis, amateur qualifier Karl Vilips, and former world No.1s Jason Day and Adam Scott - all missed the two-over cut.
Defending champion Matthew Fitzpatrick (70) of England made a hole-in-one at the short par-3 15th, the third of the week after Frenchman Matthieu Pavon and Sam Burns aced it on Thursday.
Fitzpatrick is one over through two rounds.
- with AP, Reuters
