Harper's bid to win his first career Derby was foiled by the incredible power displayed by Cespedes. But the experience was still one that he and his father will forever cherish.
"It was a great atmosphere and I got to share it with my family," Harper said. "It's a lot of fun and I was so thankful for it. I've got to thank my dad for everything he has done for me, all the numerous [batting practice] he's thrown to me. I love him more than anything in this world."
After Harper hit eight home runs in final round, Cespedes bested that total when he hit his clinching ninth home run an estimated 455 feet over the center-field wall with five outs to spare.
"I came off the field saying [eight is] not enough," Harper said. "I thought maybe 12. The way he was swinging the bat that first and second round, he wasn't even trying. It was pretty incredible to watch. He's so strong."
Harper homered on the first three swings he took in the finals. The Nationals outfielder homered on consecutive pitches after recording eight of the 10 outs the participants were allotted per round. But neither of his final two swings produced a home run.
"It was a dream come true, of course," Ron Harper said. "I wish I could have done better for him. I would have loved to have run into his bat a little more."
Still just 20 years old, Harper is the second-youngest player to ever compete in a Derby. Ken Griffey Jr. was 42 days younger when he competed in the 1990 event.
Harper's longest shot was the 471-foot homer he hit over the right-center-field wall in the first round. Prince Fielder's 483-foot blast was the only one that traveled longer.
Harper entered the second round needing to hit eight home runs to pass Colorado's Michael Cuddyer and earn a spot in the finals. He clinched the spot with the 425-foot shot he hit to center with four outs to spare.
After recording an out with his first swing of the second round, Harper hit five consecutive home runs. He admitted he started to get fatigued during the final two rounds.
"Right now, I'm feeling pretty tired," Harper said. "Those last two rounds, I was a little tired. But it was a lot of fun and I had a blast doing it."
Harper looked at the first three pitches before using his first swing of the night to hit a ball an estimated 455 feet over the center-field wall. He showed patience throughout the event as his father threw what appeared to be cut fastballs.
Ron Harper was simply throwing to his son in the manner that he had countless times before under the Las Vegas sun. But this time, he had the thrill of doing so while wearing a big league uniform, adorned with No. 3, the number he wore while playing a variety of sports during his youth.
After throwing his final pitch of the night, a proud father expressed his appreciation to his son.
"I said, 'Thank you for the opportunity to do this with you, kid' and 'I love you,'" Ron Harper said.