SAN FRANCISCO (AP) -- Somewhere along The Olympic Club's tight, twisting fairways, 17-year-old Beau Hossler went from thinking he could be the low amateur to believing he could win the whole tournament.
Apparently he wasn't the only one.
Tiger Woods' agent approached Hossler's dad outside the scorer's room late Saturday afternoon, shook his hand and said, "This is unbelievable. He can win this thing."
Ten minutes later, after signing for an even-par 70 that left him tied for eighth - four shots off the lead - in the U.S. Open, he reiterated that sentiment.
"Absolutely," said Hossler, who earned a standing ovation from spectators above the historic 18th green. "There's not a doubt in my mind. Got to go out there and do everything right mentally and physically. But it's definitely out there for me."
While fans would serenade Mickelson with a chorus of "Happy Birthday" when he finished No. 18, they gave the kid in braces a standing ovation, shouting "Hook `Em Hossler" for his commitment to play at Texas in 2013
"I turned to him and said, `How good is this?' Just enjoy it," said caddie Bill Schellenberg, Hossler's godfather. "He just looked at me with a huge smile."
Hossler already has made history - becoming the first since Mason Rudolph in 1950-51 to qualify for consecutive U.S. Opens as a high school player.
But a Sunday victory would make him one of only six amateurs to win a U.S. Open - putting him in the company of Francis Ouimet and Bobby Jones, who did it four times.
Hossler couldn't name an exact moment when his goals changed.
But being able to battle back from every bogey he posted Saturday surely had something to do with it.
"I backed them all up with a birdie," Hossler said matter-of-factly.
Schellenberg, who kept Hossler loose by cracking jokes, wasn't surprised.
"He has really good resolve. The kid doesn't quit. It's just awesome," Schellenberg said. "He has an unbelievable ability to get upset, get it out and get it over with and get onto the next shot. I don't know what it looked like, but he and I were having a grand time."
Hossler followed up a bogey at No. 3, with a birdie at No. 4. He did the same at Nos. 6 and 7, Nos. 11 and 12, and Nos. 13 and 14 before closing out his round with four straight pars.
There also was a clutch two-putt for par on the 188-yard eighth hole, and a par save on No. 9 after he hooked it into the trees.
"That was huge," Hossler said. "But I think the biggest one was on 13 where I got up-and-down for bogey from down in the swale. Double-bogeys really kill you and fortunately I was able to salvage a bogey but it actually felt like a birdie there."
It's been quite a week for Hossler, who played a practice round with Furyk and another with fellow Southern Californian Mickelson.
In the latter, he claimed bragging rights, if not actual money, with a 1-up win during partner match play. Contrary to reports, his dad said it was a friendly match, and no money actually changed hands - though there was plenty of joking about only playing for $20 a hole.
That would be peanuts compared to the $1.44 million Hossler, as an amateur, would miss out on if he were to actually win Sunday.
Hossler, at 17, isn't even old enough to celebrate with an adult beverage, and the most adult thing he's done recently was ask his mom if he could drink coffee to help him stay up to study for finals.
On the golf course, his poise belies his youth.
"I had a great day," Hossler said. "I went out there and didn't really have any expectations except to make sure that I'm getting the most out of my round."
Thousands on TV saw what dozens of family members and friends following him around Olympic Club already knew.
The kid can play.
"It's amazing," Hossler said of the support. "I can't tell you how much I appreciate the support out there, not only from my family and friends from home, but all the people in the Bay Area. It's really special."