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Phil Mickelson has won four majors. Billy Horschel has won once on the PGA Tour, and that was less than two months ago.

Mickelson was displaying his usual take-a-chance flair Friday. His round at the U.S. Open was the full package of par saves and makeable birdie putts that all went awry — until he finally sank one from 20 feet at the 18th, the hardest hole on the course, to tie him with Horschel for the lead seconds after the horn sounded to suspend play for the day.

Dramatic stuff, Lefty.

"On 18, when you don't really expect to get one, I put the ball in a good spot and was able to roll one in," Mickelson said.

Horschel's approach to top of the leaderboard was much more straight-forward. He merely put the ball on the green in regulation 18 times out of 18, a stellar achievement for regular tour event, much less a U.S. Open. His 3-under 67 was the best round of the day, and he and Mickelson had a 1-under 139 total that made them the only players under par nearing the halfway point of the championship.

"I wasn't in the zone, I was just focused on what I tried to do," said Horschel, who missed the cut in his only previous U.S. Open appearance as a teenager in 2006. "I didn't know I hit every green until I walked off 18. It's a cool thing."

Yeah, pretty cool, especially when considering that Justin Rose and Steve Stricker were the only other players to shoot a red number in the second round at Merion. Both carded a 69 to stand at even par for the tournament, tied with Luke Donald (72) in the clubhouse for second place. Ian Poulter and amateur Cheng-Tsung Pan of Taiwan also were at even par but had yet to finish the back nine.

Nearly half the field was still on the course when play was called due to darkness. Groups are allowed to complete the hole they're playing after the horn sounds, so Mickelson's birdie at 18 was the golf equivalent of hiking the football before time runs out and getting to complete the down. In fact, his group was so eager to finish the round that they negotiated with the group ahead for playing partner Keegan Bradley to hit his tee shot early at 18.

"We need to hit one tee shot so we could finish," Mickelson said. "They moved out of the way, and Keegan hit a tee shot and they went back and finished the hole. ... It's nice when guys like that help out."

Weather wasn't a problem Friday, but Thursday's storms meant the first round spilled over into a second day and delayed the start of Round 2 by a few hours. The second round was set to resume at 7:15 a.m. Saturday.

No matter the tee time, the players are finding Merion's wicked rough and flummoxing greens to be a challenge, even though it's the shortest major championship course in nine years.

"It's hard with the wind and the pin locations," said Tiger Woods, whose ailing left elbow flared up again in his second-round 70 that left him at 3 over for the tournament. "They're really tough. ... We didn't think they were going to be as severe as they are."

Horschel figured out the course enough to make four birdies and one bogey, which shouldn't be too much of a surprise. He's having a breakout year, with six finishes in the top 10 on the PGA Tour, including his victory at the Zurich Classic in late April.

"I've acquired some patience, not as much as I wish I had," said the 26-year-old from Jacksonville Beach, Fla.

Still, he's no Mickelson. The most recent personal buzz about Lefty was his decision to attend his daughter's eighth-grade graduation ceremony on the eve of the Open, then fly cross-country overnight to play his first round Thursday on little sleep.

Horschel? Well, his official PGA Tour bio says that he "read all four Twilight books in two weeks and is a believer in Bigfoot and UFOs."

He's also said he's steadied his game with the help of sports psychologist Fran Pirozzolo, who helped convince Horschel to think of the U.S. Open as "another tournament."

"I know it's a big event. I know it's a historical event," Horschel said. "But one thing that me and Fran have worked on is limiting the distractions."

It certainly worked on Friday.

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