The 14-year-old Asia-Pacific Amateur champion hit a delicate downhill lag putt at 18 that stopped two feet from the cup and then made par to complete a 73-75-77-75 set of rounds for a 12-over 300 total as low amateur.
After doffing his baseball cap to the applauding gallery at the last, Guan said he was unsure about his upcoming plans after winning so much attention at the Masters.
"We have a couple invitations for me," he told reporters. "So we have to consider what to play, what not."
His mother, Guan Hong Yu, told Reuters the family was heading to New Orleans to stay with a friend who lives there.
"Last year we spent one month with her in New Orleans," she said.
The PGA Tour happens to stop in New Orleans in two weeks for the Zurich Classic.
"If we get an invitation, then we will consider," a friend of the Guans said with a smile.
Meanwhile, Guan was enjoying the glow of a major championship debut in which he suffered no three-putts and nothing worse than a bogey on his scorecards. A one-stroke penalty for slow play on Friday was his only hiccup.
Guan came to Augusta three weeks early to get acclimated and learn about the famed Masters course.
In the final run-up to the tournament, Guan played practice rounds with two-time champions Ben Crenshaw and Tom Watson, and nine holes with four-time winner Tiger Woods.
Asked about the best advice he had received, Guan said: "Mr. Ben Crenshaw said just play my own game and have fun."
Guan did just that, and said the Masters was his biggest accomplishment so far.
"It's such a great week for me and I enjoy it so far and learned a lot," he said.
"There's still a lot of things to improve. My short game's good, but still needs to be better. My driver probably needs to be longer. Everything needs to improve," he said breaking into a smile.
Guan was already a winner to his father.
"I'm so happy. I'm so proud of him in front of so many patrons in such a great tournament," said Guan Han Wen, a doctor who introduced his son to the game when he was four. "He felt very nervous but played his game, so I'm so proud."
As Guan walked away from the 18th, he made another young boy happy when he walked over to the restraining rope and plunked his ball into the hands of 12-year-old Lee Baker.
"I just wanted to clap for him but he gave me the ball," Baker said. "He's good. I know he's from China and that he's 14. We went to the Par-3 Contest and we watched him."
Guan said he was not contemplating turning professional any time soon.
"I've not decided yet, but it won't be too early because there's still a lot of things to learn to improve. So nothing to rush."
Except, perhaps to catch up on homework.
While Guan has had a lot of practice with his English, speaking to reporters at Augusta National, there has been little time for his Chinese, math and science studies.
Asked if he had been able to keep up with school responsibilities this week, Guan said: "Yeah, probably tonight."
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