Sebastian Korda pocketed over $200 000 from his run to the Roland Garros last 16 but was more pleased by convincing childhood idol Rafael Nadal to give him a signed shirt.
Korda, the world number 213 who came through qualifying in Paris, went down 6-1, 6-1, 6-2 to 12-time champion Nadal on Sunday in the fourth round.
But the son of 1998 Australian Open champion and 1992 Roland Garros runner-up Petr Korda was delighted by the opportunity to share the same court as the 19-time Grand Slam champion.
"It was definitely the best moment of my life, super awesome," said the 20-year-old.
"After the match I asked him for a signed shirt when we were tapping rackets. I don't know if anyone's ever asked him for an autograph after a match, but that was definitely the coolest moment of my life and one I'll never forget for sure.
"Rafa was unbelievable. He said no problem. So I have one in my bag right now. So I'm super stoked."
Korda, a former world junior number one, made his Grand Slam debut at the US Open before coming to Paris to successfully qualify for a major for the first time.
He talked on the eve of his clash of his respect for 34-year-old Nadal, a devotion so deep that he named his cat after the great Spaniard.
On Sunday, he was even willing some of Nadal's whipped forehands to land in.
"He almost hit an around-the-net forehand and I was kind of begging for it to go in because that would have been the coolest thing ever," he said.
"And then he hit a running forehand winner on me at the lines. I just said to myself, This is awesome. I learned a lot.
"The score wasn't the closest, but every game was pretty close. So I took a lot of confidence in that and knowing that I have a big enough ball that I can hurt some of these guys."
Nadal, for his part, was fulsome in his praise of Korda, describing the American's backhand as "amazing" but offered tips to a player whose challenge wasn't helped by 48 unforced errors.
"He just needs to adjust a little bit the mistakes sometimes with the forehand. But he's able to take the ball early, he takes the right position on court. From inside the court he's able to dominate the point.
"He's quite tall so he can keep improving a little bit the serve, that I'm sure he will."
Victory on Sunday allowed Nadal to reach the Roland Garros quarter-finals for the 14th time, staying comfortably on course for a record-equalling 20th Grand Slam crown.
It was a 97th win at the tournament against just two defeats since his title-winning debut in 2005 and allowed him to book a 42nd appearance in the last eight of a Grand Slam.
Next up on Tuesday is another young pretender, 19-year-old Jannik Sinner of Italy who stunned sixth seed and US Open runner-up Alexander Zverev 6-3, 6-3, 4-6, 6-3.