At one point, as 15-year-old Kai Beckstrand was breezing through the “American Ninja Warrior” obstacle course that even professional athletes and longtime competitors on the show struggle to complete, an announcer shouted: “He’s making this course look like child’s play!”

And for Kai, who has been training for the show since he was 7, maneuvering through the 40-plus obstacle courses his dad engineered and built in their St. George, Utah, backyard over the years, maybe it was.

The teenager ran the entire course in 1:38:83 — beating the fastest time of the night by 15 seconds.

“It feels amazing, just even to be here,” said a slightly out-of-breath Kai after running up the 14.5-foot Warped Wall and hitting the buzzer. “But to get the fastest time, that’s insane.”

Before this season, the minimum age requirement to apply for the show was 19. But this year, with eyes on promising young competitors like Kai, “American Ninja Warrior” lowered the requirement to 15, according to the website American Ninja Warrior Nation (it should be noted that the second-fastest time of the night came from 15-year-old Cal Plohoros).

But Kai’s run on the show did more than secure the fastest time of the night and clinch a spot in the semifinals, which begin July 19. It also made “American Ninja Warrior” history.

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The high school sophomore’s successful run came right after his father, 42-year-old Brian Beckstrand, completed the course with a time of 3:23:67. That makes the Beckstrands the first father-son duo to ever hit the buzzer on “American Ninja Warrior” in the show’s 13 seasons.

Both are headed to the next round of the competition.

The Beckstrands have a fairly extensive history with “American Ninja Warrior.”

Kai Beckstrand won Season 1 of “American Ninja Warrior Junior” in 2019, and finished fourth on the show’s second season. Both of his parents have also previously competed on “American Ninja Warrior.”

Brian Beckstrand completes the qualifying course on “American Ninja Warrior.” Brian Beckstrand and his son, Kai, are the first father and son to complete the course in show history. | Elizabeth Morris, NBC

Now, Kai and his dad are competing against each other. But both are rooting for each other to make it to the finals in Las Vegas — although not without their fair share of lighthearted trash talk.

“If I beat you on the course, we might have to talk about some more chores and duties around the house,” Brian Beckstrand said ahead of their appearance on the show earlier this week.

“It’s a good thing I don’t have to worry about that,” Kai responded.

Note: The semifinal round of “American Ninja Warrior,” which features the top 30 to 35 competitors from each of the five qualifying rounds, begins July 19 and will air on NBC.