It looked like Kai Beckstrand was going to fall.

The 15-year-old from St. George, Utah — one of the youngest competitors on this season of “American Ninja Warrior” — had just finished the eighth obstacle in a demanding 10-obstacle course that puts balance and upper body strength to the test.

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He had cruised through many parts of it, dashing up the 14.5-foot Warped Wall and ascending the Salmon Ladder by pulling himself up with a single movable rung.

But now, his energy seemed to be waning.

On the ninth obstacle, called The Dungeon, Kai had to first climb up a vertical panel by using a series of spikes. About halfway up, he hesitated for a second, his legs dangling as he clutched onto one of the spikes with both hands.

“Oh no, he’s in trouble!” one of the announcers shouted.

But Kai wasn’t going to give up that easily.

He maintained his grip and kept climbing, eventually reaching the top of the panel and locking it into a horizontal position. From there, he grabbed onto the spikes and breezed across as if he was swinging on monkey bars at a children’s playground.

“We thought he was done, but we were wrong!” an announcer shouted in disbelief.

Now, Kai had just one more obstacle to go before hitting the buzzer that would secure his place in the “American Ninja Warrior” finals.

To defeat the Spider Trap, the teenager had to ascend a 35-foot chute, pushing three sets of trapdoors that each weigh 100 pounds along the way. He slipped at the start, but steadily worked his way up to the top.

He was all smiles when he hit the buzzer.

Kai Beckstrand was one of 12 people who completed the entire course during Monday night’s episode of “American Ninja Warrior.”
Kai Beckstrand was one of 12 people who completed the entire course during Monday night’s episode of “American Ninja Warrior.” | Elizabeth Morris, NBC

Of the 38 competitors during Monday night’s semifinal round, only 12 completed the entire course, according to the American Ninja Warrior Nation website. Of those 12, Kai had the fifth-fastest time — 4:56.17 — and is now one of the youngest “ninjas” competing for the $1 million prize in the “American Ninja Warrior” finals, which start next week.

“I’m so proud!” cheered his dad, Brian Beckstrand.

Kai and his father made “American Ninja Warrior” history earlier this season, becoming the first father-son duo to ever hit the buzzer and move on to the semifinals together, the Deseret News reported.

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Although Brian Beckstrand’s time on the show came to an end Monday night — falling on an obstacle that claimed seven other competitors — he will still be on the show, cheering for his son who has been training for this since he was 7, thanks to the 40-plus obstacles they’ve built in their backyard over the years.

“Me and my dad do everything together,” Kai said during Monday night’s episode. “He’s just the best training partner I could ever have.”

Note: The “American Ninja Warrior” finals begin Aug. 30 on NBC.