Philip Pettitt Jr. was hitting a few balls from the practice tees at Oakmont Country Club when he noticed the rustling of the crowd as another player stepped to the adjacent tee to take some swings.

Once Pettitt saw who it was, he could not help but step back and watch the seasoned veteran hit a few balls.

"It was Phil Mickelson," Pettitt, 22, said yesterday after he shot an 11-over 81 in the first round of the U.S. Open, "That was probably when it really hit me that this was a lot bigger than your normal amateur event. Here I am, still a college kid, and I'm hitting practice balls next to the best players in the world and going out to compete against them.

"This has been and will continue to be a great learning experience for me no matter what happens tomorrow. It has just been unbelievable."

Pettitt is one of 10 amateurs in the field for the U.S. Open, but he likely is the least experienced. He recently finished his junior year at the University of Tennessee. He was the Volunteers' top golfer with a scoring average of 73.6. He also was a first-team All-SEC pick as well as a member of the PING Division I all-region team for the Southeast.

This is his first U.S. Open, but he is confident it will not be his last, which is why he is paying close attention to how the pros prepare for a major event and how they handle themselves through every step this week.

"I think the one thing I've learned this week is that most of these guys don't hit it any better than I do. It is just an experience thing," Pettitt said. "It is course management, it is understanding how to play to score and understanding the course. That's the biggest difference, really, the experience. I'm just trying to learn as much from this experience as I can because I know this is only the first of many U.S. Opens for me."

Pettitt, whose father Philip Pettitt, Sr. is his caddie this week, has a reputation for being mentally tough. He needed that toughness to qualify for the Open. He was one of three players tied for two spots at the Rockville, Md., qualifier last week and survived a three-way, sudden-death playoff to grab one of the two spots.

He needed to make a miraculous approach shot on the third hole in order to save par and grab the spot.

This week, however, his mental toughness has been challenged, not just by one of the world's toughest courses, but by the magnitude of the event and the level of competition. He said the course is the toughest he has played, but it was a little easier yesterday than the previous two because rain softened the greens and fairways.

That said, he has held up well and, after a slow start yesterday ( 4-over-par after three holes and 9-over after nine), he finished with a respectable 2-over 37 on his second nine (he began on the back). He had two double bogeys on his first nine and two birdies on his second nine.

He said he hopes that momentum will carry over, but he knows he is a long shot, at best, to make the cut. And, while he knows he is not playing under the same pressure as the pros, that does not mean he does not feel the same frustration when things go bad.

"[Wednesday,] I played my practice round in a group with Sergio Garcia, Paul Casey and Luke Donald, so I got a good feel for playing in front of big galleries, and that was great for me because I was ready for it," Pettitt said.

"I'm not here playing with the pressure of trying to pay my mortgage or feed my family, so the pressure is a lot different for me because it is internal. I wanted to shoot better than I did, and there were a number of shots I wish I had back, particularly on 15, where I had a double bogey.

"But I felt good coming back in on that second nine, and I feel like I settled down so I'll work on some things on the range tonight and see what happens tomorrow. You never know, I've come from far behind before."

Pettitt is from Murfreesboro, Tenn., about 35 minutes southeast of Nashville and is the hometown of the late and famous sportswriter, Grantland Rice. He plans to turn pro next year after he graduates, but he has a busy summer ahead of him playing in nearly every major amateur in the country, starting with the Dogwood Invitational in Atlanta June 27.

While Pettitt struggled, several amateurs fared well enough to put themselves in position to make the cut with another solid round today. Both Rhys Davies, from Wales and a three-time first-team All-American at East Tennessee State, and John Kelly, a Missouri graduate who finished with the lowest score among the amateurs at the Masters this year, shot a 4-over 74.

Richard Ramsay, the reigning U.S. Amateur champion, played in a group with Tiger Woods and defending Open champion Geoff Ogilvy. He acquitted himself nicely, shooting an 8-over 78. He said he learned a lot from the experience, but hopes it does not end today.

"I had a great time out there," Ramsay said. "Obviously, I would have enjoyed it a lot more if I played well and I didn't do that. Some days when you are struggling, you need to just hole a few putts. I learned watching Tiger and Geoff how you get around the golf course, and I'll take that into tomorrow."