Brian Campbell the top amateur at 1 under, tied for 12th

On the walk to the 495-yard par-4 No. 4 hole, Brian Campbell glanced up at the giant electronic leaderboard that sits across the fairway. He liked what he saw.

At the time it was pretty special, he said, because he read his name as the current co-leader of the 115th U.S. Open Championship.

“I definitely want a little more of that,” Campbell said.

For three early holes during Friday’s second round, the 22-year-old, who recently completed his collegiate career at the University of Illinois, enjoyed sharing the top spot with Jordan Spieth, who was out on the course, and Dustin Johnson and Henrik Stenson, who had yet to begin their rounds.

After Friday’s 2-over 72 second round, Campbell is at 1-under 139 and tied for 12th. It makes him the top dog among the 17 amateurs who qualified for the 156-man field — five of whom will join Campbell for the weekend rounds at Chambers Bay.

Florida State’s Jack Maguire, who is using Chambers Bay caddie Jason Gilson this week, shot a second-round 68 to move to 1 over and a tie for 21st. Others making the cut were Georgia Tech’s Ollie Schniederjans (2 over), Texas’ Beau Hossler (3 over) and recent Virginia alum Denny McCarthy (4 over).

Nick Hardy, a college teammate of Campbell, bogeyed his final hole — the par-3 ninth — to finish at 5 over. It was significant because he brought all the players at 5 over along with him into the weekend rounds, which ballooned the field by 16 golfers.

Notable amateurs who failed to make the cut were 15-year-old Cole Hammer and NCAA Division I champion Bryson DeChambeau of Southern Methodist.

Campbell started hot with birdies on two of his first three holes. He sank a 23-foot putt on the 403-yard second hole, then drilled a 20-foot putt on the 207-yard third to go to 5 under with Spieth.

That lasted until the 506-yard par-4 seventh, which, like Thursday’s opening round, caused him trouble. After he pulled his tee shot left, his approach found the right bunker, and his third shot stopped 50 feet past the cup. The result was a double bogey and a fall from the lead.

“I put myself in some tough spots,” said Campbell, a native of Irvine, California. “I’ll have to figure that out, I guess. It’s a tough hole; two demanding shots it needs.”

In 2014, Campbell missed the U.S. Open cut at Pinehurst No. 2 by one shot. Having that experience this time could make a difference, he said.

“As long as you play your game and play well, hit good shots, you can compete out there,” he said.