Practice may not actually make perfect, but for Michael Thompson on Thursday, it made for a pretty good round.

Thompson shot a four-under 66 to take the early lead at the U.S. Open at The Olympic Club, all while drawing on an experience from five years before.

Back in 2007 on the same course, Thompson was battling Colt Knost for the U.S. Amateur Championship. Knost came out on top, winning a 2 & 1 decision during a 36-hole finale, and the USGA put the players in the same threesome for the first two rounds.

But despite the loss in that USGA championship, Thompson's success Thursday can be partially credited to the 2007 experience.

"I almost played, I guess 11, rounds in nine or ten days and you play a golf course, any golf course that many times you're going to know where to hit it," Thompson said. "I don't know, I just fed off those vibes. I hit a lot of good shots, made a lot of good putts that week, and obviously off to a great start this week."

Thompson's experience on the Lake Course at Olympic Club isn't limited to the 2007 U.S. Amateur. He arrived the Friday before championship week to practice and find a good strategy come the opening round.

"That was really big to be able to spend three full days really with nobody out here," Thompson said. "I had the chipping green, putting green, all to myself. I really got some good practice."

The 27-year-old, who is in his second year on the PGA Tour, said that repetition allowed him to find the right lines off the tees and figure out his approaches.

Thompson said that he often tried to get the ball on the greens -- which were playing very fast Thursday -- by hitting it on the front edge, or several yards shy of the putting surface. The strategy paid off, as he needed just 22 putts.

He admitted that the course is a little bit different than when he played it in '07, but the experience gave Thompson an advantage beyond knowing how to play the course.

The experience allowed Thompson to be comfortable Thursday -- at least, that is, until the television cameras showed up.

He was comfortable because he's staying with the same people who housed him in '07.

"Jim and Joanne Hickman. They live on Lombard Street, on the crookedest street in the world," Thompson said. "It's been a joy to be able to spend time with them, kind of reminisce on days past and just enjoy this new experience."

And he was comfortable because one of his playing partners during the first two rounds is Knost, who struggled to a five-over 75 on Thursday. Thompson said Knost didn't have the best first round, but expects him to fight back.

"Today was fun with Colt," Thompson said. "We talked about the U.S. Amateur and the changes with the golf course from then till now. And just joking and just enjoying, I guess, each other's company."

And, of course, Thompson was comfortable because of the amount of golf he's played at Olympic.

After gaining entry to the U.S. Open by playing well at the mid-Atlantic qualifier in Maryland, Thompson is so far making the most of his chance. He said he doesn't fully expect to stay at four-under, and knows patience will be key Friday.

But for now, Thompson can be satisfied knowing that, five years after being in contention at one USGA championship, he's leading another.

"I've been looking forward to hopefully playing in this event for over two years, since the U.S. Amateur in '07," Thompson said. "I just can't be more thrilled."