ERIN, Wis. -- Brian Harman looks at the company he has at the top of the U.S. Open leaderboard and can't help but think that the demanding Erin Hills layout has something to do with the crowd he finds himself in.
Harman, Paul Casey and Tommy Fleetwood of England and Brooks Koepka will enter the weekend in a four-way tie for the lead. All four finished Friday's second round at 7-under-par 137 playing a course that prevented the world's three top-ranked players from moving on.
While Dustin Johnson, Rory McIlroy of Ireland and Jason Day of Australia all failed to make the cut on Friday, the championship chase will begin in earnest on Saturday with the U.S. Open wide open and there for the taking.
"I think that's a testament to how good the golf course is and how well it's set up," Harman said. "There's a lot of different ways to play it."
Friday proved just that.
The tournament-leading foursome held a one-shot lead over a trio of contenders that includes first-round leader Rickie Fowler. Jamie Lovemark and J.B. Holmes join Fowler a shot back and five other players are within two shots of the lead.
Casey remained at the top of the leaderboard despite temporarily falling off Friday morning when he struggled through a stretch that included two bogeys and a triple bogey.
But Casey rebounded with five straight birdies at Nos. 17, 18, 1, 2 and 3 to find his way back to the top before Harman, Fleetwood and Koepka -- all of whom shot 70 on Friday -- made an afternoon charge.
"It's not every day you enjoy a round of golf with an 8 on the card, but I'm a pretty happy man," Casey said. "It was a bit of a roller coaster."
Fowler, meanwhile, entered the round with a one-shot lead over Casey and Xander Schauffele, who is now in the group at 5 under. But after a blistering 7-under 65 to start the tournament, Fowler posted three straight bogeys on Nos. 11, 12 and 13 as he missed makeable putts on each hole to fall off the pace before finishing with a 1-over 73.
Despite the issues, though, Fowler remains in contention for his first major championship.
"I hate just being in the situation where I've been in a good spot and maybe let it get away from me a little bit and let some mistakes compound and turn a round that you (just) kind of fight through it and end up being in a decent spot after the day," Fowler said.
"I'm playing the weekend. I have a tee time on Saturday (and) so you just kind of learn along the way to never really give up."
Friday wasn't nearly as favorable for the world's three-top ranked players, none of whom will move onto the weekend.
Johnson, ranked No. 1 in the world, missed the cut after a 1-over 73, which came a day after he shot 75. Johnson struggled with his putting throughout the day, which included four bogeys.
The No. 2-ranked McIlroy and the third-ranked Day also failed to advance to move after struggling for a second straight day. McIlroy shot 71 and finished at 5 over after 36 holes despite shooting 4 under on his final six holes.
McIlroy has played in only seven tournaments this season and was coming off a layoff resulting from a nagging rib injury. McIlroy played in the same group with Day, who had a 7-over 79 on Thursday and followed with a 75 to finish at 10 over.
Despite their respective struggles, neither Johnson, McIlroy or Day took issue with the course, instead taking ownership of the problems that cut their weekend short.
"If you look at this golf course and you talk to me, Jason or Rory, this golf course sets up perfect for us," Johnson said. "But as we all know -- this game is all about putting. So it's pretty simple."
He added: "It doesn't matter how good you hit it, if you struggle on the greens, there's nothing you can do."
NOTES: Japan's Hideki Matsuyama and Chez Reavie each posted a 7-under 65, which represented the day's lowest scores a day after Fowler posted the same score. Matsuyama will enter Saturday tied for eighth and Reavie will begin the weekend tied for 13th. ... 2016 Masters champion Danny Willett of England withdrew before his afternoon tee time with a back injury. Willett struggled to a 9-over 80 in the opening round before announcing he would not return. ... A 94-year-old Wisconsin man died of natural causes during the second round. Local sheriff's deputies and rescue workers were called to the grandstand by the No. 6 hole, where the man was reported not to have a pulse or be breathing. The man, who was not identified, was transported to an on-site ambulance, where he was pronounced dead. No foul play is expected, according to local authorities.