LOS ANGELES -- Rickie Fowler was ready to walk off the final green at the U.S. Open with the solo lead heading into Sunday's final 18 holes. But as the marine layer rolled into Los Angeles Country Club and evaporated every bit of sunlight Saturday night, Fowler stepped up to a short par putt on the 18th hole and missed it.

The lip-out prompted a gasp through the surrounding gallery and left Fowler befuddled.

"I'm not sure why it didn't move," Fowler said of the putt. "It should have. I hit a good putt, so really can't go back on it, obviously. Just a bummer."

Fowler's bogey left the door ajar for his playing partner, Wyndham Clark, who was sitting at 9-under and had hit his best shot of the day -- a 9-iron that nearly hit the cup and prompted a vicious club twirl -- into the 18th. Clark sank the short birdie putt to card a 69 that put him at 10-under, giving him a share of the lead with Fowler and a spot in the final group.

Rory McIlroy was one shot back in third, and Scottie Scheffler, the No. 1 player in the world, was three back.

"I'm not a huge scoreboard watcher, but walking up there I kind of knew where we were at," Clark said. "I really wanted to be in that final group."

Clark said both his bogey putt on 17 and his birdie putt on 18 were hard to read given the sudden darkness that fell over the course. He also said he felt Fowler's putt was missed, in part, because of how dark it was, too, and added that he felt it had to do with the pairing's late 3:40 p.m. tee time.

"It's a little ridiculous that we teed off that late," Clark said, adding that he and Fowler could have called the round off on the 18th green. "We played twilight golf. I'm not trying to make an excuse, but it definitely was a challenge. It's kind of tough and it's crazy to think that we're doing that on the last two holes of a major when we could have teed off two hours earlier."

The final grouping of Fowler and Clark will tee off at 2:30 p.m. Sunday.

Fowler and Clark are connected by more than their score or the fact they played golf at Oklahoma State and are searching for their first major victory. As they made and missed putts off that 18th green Saturday, they also shared something else that was going to keep them together for another round: a putter.

Much like Fowler had tried his caddie Rickie Romano's putter and fell in love with it enough to play a similar version, Clark had done the same. After seeing how many putts Fowler was making, trying the putter while they played at Medalist Golf Club in Florida, Clark tried the Odyssey Versa Jailbird himself and was sold.

"I texted the Odyssey guy, and I said, 'Hey, can you make me Rickie's putter?'" Clark said after Saturday's round. "And he's like, 'Well, what specs?' I said, 'The exact same.' So literally had the exact same putter. And I joked with Rickie today, he changed the grip. He changed the grip and cut it an inch, so I was like, 'All right, I got to change the grip and cut it an inch.'"

Putting has been key for Clark and Fowler this week. Both are averaging the fewest putts per hole in the field, and Fowler led the field in strokes gained putting Saturday. Both have also made long-range putts in key moments. On the 13th hole Saturday, Fowler made a 70-foot birdie putt that Clark followed with a 12-foot birdie putt to stay close. The two went back and forth all day and were never separated by more than two shots.

"I handled all the adversity," Clark said. He had back-to-back bogeys at one point and said after the round he was nervous throughout most of the day. "I feel like my best round is still out there."

Clark is five years younger than Fowler and remembers not just looking up to the Oklahoma State alum when he was in college and Fowler was blowing up the golf world, but also how willing Fowler was to return to Stillwater and spend time with the golf team.

"Even when I came out [to the PGA Tour], he's always sent me notes of good playing," Clark said. "Or even at some tournaments he would tell me, 'Hey, I think this is a better play to play off the tee.'"

It's safe to say Fowler won't be giving Clark any tips come Sunday, but regardless, the final grouping will probably feel less like a duel and more like a competitive round between friends. This time though, it'll be with the U.S. Open on the line.

"Everyone's pulling for Rickie," Clark said. "I'm the underdog."

Fowler didn't quite see it that way, but it's easy to see why the crowds at LACC have been chanting his name and cheering more loudly for him since Thursday. His career has seen him rise, fall and now rise again to have a chance to add a coveted major to his resume.

Clark and Fowler will have to contend with more than just each other on Sunday, though. The penultimate group will feature two of the top three players in the world in McIlroy, who grinded out a 69 to finish at 9-under, and Scheffler, who finished with an eagle and a birdie to stay in the mix at 7-under heading into the final day.

As the two major winners chase the first-time hopefuls, there will no doubt be plenty of pressure to go around Sunday. For Fowler, that pressure could have, at one point in his career, been overwhelming, even debilitating. But according to him, things are different now.

"This is the best I've felt, let alone in a normal tournament but especially a major, and I would say really ever in my career," Fowler said. "After going through the last few years, I'm not scared to fail."