SCOTTSDALE, Ariz. — To understand why the Rockies’ Nolan Arenado is a perennial MVP candidate, and why his first cousin, Josh Fuentes, is an up-and-coming Rockies prospect, you must first understand the Arenado-Fuentes family dynamic.

“The sports and games they played were always extreme, always over the top,” said Mercedes Arenado-Melian, Josh’s mom and sister to Nolan’s father, Fernando.

“I mean, even when we played Charades it was like that,” she continued. “When one team won the game, the music would suddenly start blaring and they’d all be talking at each other. Nothing was ever simple, everything was over the top.

“That competitiveness is a huge component of who they are, what they have done. It helped them break down barriers and showed them what they needed to do if they wanted to succeed.”

Within the Arenado-Fuentes universe in Orange County, Calif. — the brother and cousins all lived within a 10-minute drive of each other while growing up — the nonstop gauntlet included ping-pong tournaments that lasted until 2 a.m., two-on-two basketball games, family golf tournaments and soccer matches that coincided with the World Cup.

Competition produced black eyes, bruised feelings and wounded egos, yet those things were always — eventually — soothed by love and camaraderie.

“It made me super-competitive and I hated losing, because you’d never hear the end of it,” Nolan said. “But it was always fun. We loved it.”

Said Millie Arenado, Nolan’s mom: “They are very close, but they don’t like to lose. They are super competitive; it’s fierce. It molded them, and, No. 1, it helped them stay out of trouble.”

Last fall, the Arenado-Fuentes clan drove from their home base in Orange County to watch Josh play third base in the Arizona Fall League. After the game, the real competition began.

The gang of six was a combustible mixture of brothers and cousins: Nolan and his younger brother Jonah, a third-base prospect with the Giants; Josh and his older brother, Justin “Tico” Futentes; and cousins Alex Luaces and Gerardo Arenado.

The gang found a park in Scottsdale where they played a five-game series of whiffle ball. A folding chair served as the strike zone and kicked-off shoes were turned into bases. The epic battle came down to Game 5, with Josh on the mound, pitching a shutout and holding a 4-0 lead going into the last inning.

Then, much to Josh’s everlasting regret, it all fell apart. It started when Nolan reached base with a single. Then Tico launched a grand slam on what Josh called “a hanging curveball.”

“I mean, Nolan didn’t even hit the homer — Tico hit the ‘granny’ — but Nolan was all in my face,” Josh recalled. “So now I’m ticked off. And the next inning, I struck out, so I’m feeling extra bad. Then Nolan hit a homer in extras to win it. Even now, I still hear about that game-tying grand slam. I’ll hear about it forever.”

Josh, a 25-year-old, undrafted third baseman out of Missouri Baptist, is in big-league camp for the first time. He signed with the Rockies in 2014 for $10,000 and with little fanfare. He was always a late bloomer and played varsity baseball for just one season at Trabuco Hills High School, hitting .250 as a senior.

He struggled early in his pro career. He stumbled at the plate at Low-A Asheville in 2015, so the Rockies sent him back to Asheville to begin 2016. He responded by hitting .398 with a 1.120 OPS over the first 28 games, earning a promotion to High-A Modesto.

Josh’s ah-ha season came last year at Triple-A Albuquerque, where he batted .327, posted an .823 OPS, smacked 14 home runs and drove in 95 runs. He was named the Pacific Coast League MVP, as well as rookie of the year. He also was named the Triple-A All-Star Game MVP. Success earned him a spot on Colorado’s 40-man roster and an invitation to big-league camp.

“I think it’s pretty rare to have a family like ours,” Nolan said. “So to have Josh in camp is a blessing for us and our families, because I know how excited everybody is about it. He’s worked hard to get here, but he has to continue to work hard, which he will.”

The turning point, for both Nolan and Josh, came in June 2009 when Nolan was drafted by the Rockies in the second round when he was 18 years old. Josh was 16.

“Josh was a little bit overweight then and he wasn’t doing all that well in baseball,” his aunt Millie recalled. “Then all of a sudden, he started running and he started to lose weight. Physically, he made a major change and then all that competitive spirit really came out.”

Josh also began channeling his passion for baseball. For the rest of the summer, almost every day, he hopped the chain-link fence at his high school to practice hitting, fielding and throwing — until it was too dark to see.

“When Nolan got drafted, things started changing,” Josh said. “Instead of us just being inside our little bubble in Orange County, the whole world kind of opened up with possibilities. Now the world’s kind of looking in at us.”

When the Cactus League games begin next Saturday, Nolan will get the bulk of the starts, but will depart after a few innings. Then it will be Josh’s turn to show what he can do.

He’s not lacking confidence.

“I will die saying this,” Josh said. “I think I’m better than Nolan.”

Wait, better than a six-time Gold Glove winner, four-time all-star and reigning National League home run king?

“I really think I am,” he said.

Does his older cousin know this?

“Yes, he does,” Josh said, flashing a mega smile. “But he would, obviously, never, ever give me that. But it’s fun to be here with him. The first day we were here, we were taking groundballs together, it was a blast. It was fun talking trash, just like always.”

Well, Nolan, does Josh have what it takes to steal your job?

“He can try.”