The 'crazy' reason why Mookie ...

It took Mookie Betts five swings to know it was over.

The Dodgers superstar had entered Monday night’s Home Run Derby aiming simply to not finish last.

The only problem: He quickly realized he didn’t know how to hit home runs, not on demand against batting practice pitches anyway.

“It sounds crazy,” Betts said with a laugh. “But I just don’t know how to do it.”

Indeed, on a night Vladimir Guerrero Jr. won the Derby with 72 total home runs over three rounds, Betts managed to hit only 11 in his first (and all but certain last) time participating in the event.

“Twenty-six was reachable,” Betts said. “But, it’s reachable for someone who knows how to hit home runs.”

On the surface, it seems like a skill Betts has mastered. He entered the All-Star break tied for third in the majors with 26 regular-season blasts this season. His 239 career blasts are 13th-most in MLB since he entered the league in 2014.

Those long balls, however, happen in live game action, where Betts’ compact swing can turn around high-velocity fastballs and thump breaking pitches left over the plate.

The soft-toss pitches Dodgers first base coach Clayton McCullough delivered to Betts in Monday’s Derby, on the other hand, require the hitter to generate more isolated power — something the 5-foot-9, 180-pound Betts couldn’t produce enough of in his 3½-minute session.

“I went through like three different swings in the middle of it,” Betts said. “I was trying. But I just kept hitting line drives.”

Of Betts’ first 12 swings, only two cleared the wall in left field. After hitting his next four in a row out, Betts managed only five the rest of the way.

“I knew it was over,” Betts said. “I couldn’t get it up in the air.”

The 30-year-old former MVP was so resigned to his last-place fate, he didn’t even use his timeout during the main three-minute segment, when he hit all 11 of his homers.

“I wasn’t tired,” he said. “And it wouldn’t have helped.”

Before a 30-second bonus period, teammate J.D. Martinez tried to give Betts some advice.

“Just pull the ball in the air,” said Martinez, who was mic’d up by ESPN.

Betts laughed and responded: “I don’t know how.”

Despite his performance, Betts was invigorated by the overall experience.

He wore his hat backward as a tribute to former Seattle Mariners legend Ken Griffey Jr. He used a custom-painted bat, one adorned with his trademark gold chain and a set of bowling pins (his other favorite sport) near the end of the barrel.

And after being eliminated, he was all smiles on the field, embracing Guerrero, Martinez and his other All-Star Dodgers teammates after checking yet another career objective — participating in the Derby at all — off his list.

“The whole thing is super cool. It got my juices flowing a little bit. That’s always fun,” Betts said. “The main thing was that, this is not for me. That’s the best takeaway I got.”