Holmes is a possible contender for a US Ryder Cup wildcard
American JB Holmes will take a one-shot lead into the third round of the 90th USPGA Championship after another brutal day at Oakland Hills.
Holmes shot 68 to edge to one under with England's Justin Rose (67), American Ben Curtis (67) and South Korea's Charlie Wi (70) on level par.
Conditions became more difficult as the day wore on and Holmes' early lead was never threatened.
Sergio Garcia was two over after a 73 and Phil Mickelson ended three over.
Penal rough close to fairways and greens and slick, hard putting surfaces were the cause of much angst as most of the 156-man field struggled on the course dubbed "the monster".
"It's easily the hardest golf course I've played," said Garcia, who double-bogeyed the short 17th.
It's the kind of round I've been looking for to get myself back on the leaderboard and feeling the good vibes
Sweden's Henrik Stenson and America's 2001 champion David Toms also reached the safety of the clubhouse early to sit at one over after rounds of 69 and 70 respectively.
Alongside Garcia on two over were Argentine Angel Cabrera, Americans Brandt Snedeker and Ken Duke, Australian Aaron Baddeley and India's co-overnight leader Jeev Milkha Singh.
World number two Mickelson, the 2005 USPGA champion, gave himself plenty of chances but struggled to make any putts and dropped three shots in his last five holes.
Holmes, Rose, Curtis and Wi, though, were delighted with their efforts.
"I hit the ball really well today," said the 26-year-old Holmes, who is on the fringes of the US Ryder Cup team. "Sixty-eight is a great score. I am glad I got in with that but I also felt I left a few out there."
Obviously I'm still just having a hangover after winning the Open
Rose, who is clinging on to the final automatic qualifying spot for the European Ryder Cup team, added: "I'm ecstatic with that round of golf.
"It is my round of the year for sure. It's the kind of round I've been looking for to get myself back on the leaderboard and feeling the good vibes.
"The key for me to play good golf is to not get ahead of myself and think about Ryder Cup."
Curtis, the surprise 2003 Open champion, said: "I know I can win another [major]. It's all about taking the opportunities I'm given."
Double Open champion Padraig Harrington, Birkdale runner-up Ian Poulter and Scotland's Alastair Forsyth were in a group on five over, along with JM Singh's fellow overnight leader Robert Karlsson, who shot 77.
"I just ran out of steam," Harrington said. "It was a struggle for me. I did my best to be ready for the week but clearly I'm not. What can I say, the harder I tried the worse it got. I haven't got the focus this week. I'm just not with it.
"Obviously I'm still just having a hangover after winning the Open."
Poulter, also chasing a Ryder Cup spot, added: "You are just trying not to bleed to death out there. It's just like the PGA slice your throat on the first tee, and you have to try and make it round to the 18th without dying."
Paul Casey, Graeme McDowell, Ernie Els and Retief Goosen were among those to finish six over, while Argentine Andres Romero, who was in the lead at two under after 16 when play was called off on Thursday, slumped to seven over after a 78.
The cut came at eight over and Casey said: "I honestly think that anyone who makes the cut has a chance of winning."
Among those to miss out were Darren Clarke (+11), Vijay Singh (+12), Ross Fisher (+13), Oliver Wilson (+14), Lee Westwood (+15), Nick Dougherty (+19) and Colin Montgomerie, who ended 20 over after a second-round 84.
"It's very difficult out there and I made it more so," said Montgomerie.
American Hunter Mahan, who claimed players were treated like "slaves" at the Ryder Cup, also finished on 20 over.