SCOTTSDALE, Ariz. – Rockies outfielder David Dahl knows how to get the goat of star third baseman Nolan Arenado.

The last swings of batting practice often devolve into a home-run-hitting contest between the two, as this tweet from @ddahl21 from Tuesday shows.

The two started taking pregame cuts together when Dahl was called to the Majors last season. One morning on a practice field, Dahl pulled a fly ball that landed short of the wall in right field, looked at Arenado and said, “That’s a home run if it’s in a game.”

Arenado, so shocked that his face developed wrinkles, broke into an incredulous, “What?” He was shaking his head, not waiting for Dahl’s explanation.

It’s a pairing of outwardly opposite personalities. Arenado’s eyes shoot daggers; his face screams intensity. To know how Dahl is feeling, you’d have to study his face and measure the width of his easy smile. Yet, they have not only developed batting practice rapport, but -- as last year attests -- the relationship has tangible effects on the performances of both.

Arenado, 28 on April 16, has established himself as one of the Majors’ top power hitters, by winning or tying for the National League home run title in three of the last four years. Dahl, 25 on April 1, has offered snippets of the same, with 23 homers in his first 140 Major League games. The Rockies hope their affectionate pregame banter leads to production that will help the team to the postseason.

Arenado and Dahl began taking turns together last season, when Dahl was called up from the Minors. Dahl, as any less-experienced player would, studied Arenado, even though Dahl bats left-handed and Arenado is a righty. But, in a delightful surprise to Arenado, Dahl wasn’t afraid to shoot a barb.

“A lot of people may be afraid to approach me because I’m intense, and they’re afraid I’m not going to take the joke the right way,” Arenado said. “But it’s all cool.”

While picking up batting ideas, Dahl was also collecting needling material. And comparing their home run spray charts never gets old.

Arenado is making a living -- having signed an eight-year, $260 million contract in February -- with pull-side home runs, 73.7 percent, but just 5.9 percent have gone the opposite way. Dahl’s go all over the place -- 43.5 percent pulled to right, 30.4 percent straightaway and a healthy 26.1 percent the opposite way.

“He just teases me, says, ‘You can’t go oppo, ever. … I can go oppo, but Arenado never can go oppo for a home run,’” Arenado said, laughing.

Wednesday's 5-3 victory over the D-backs provided more fodder. Arenado powered a third-inning pitch to right field, but the wind didn't quite take it out. An inning before that, Dahl barely missed an opposite-field homer when the ball hit the top of the left-field wall. He settled for a double.

“We call it backside home runs,” Dahl said, meaning you have to put your backside into a swing to push a homer the other way. “We just mess around with it. I try to do it in [batting practice] a lot just to show him, but he's got power, obviously. He hits 40 home runs a year, so I try to learn from him.”

Even with the joshing, Dahl has time to pick up tips.

When Dahl recovered from the rib issue that cost him the 2017 season, and an illness at the start of last season, he arrived in the Majors with a habit of holding his bat unusually far from his body.

Dahl said that at one point his dad brought it to his attention, but … you know how kids are. Then in studying Arenado, he saw that dad was right. With hands closer to his body, Dahl homered 14 times in his final 50 games -- nine in 24 September games. Not even missing 54 games with a broken foot in June, July and early August slowed Dahl’s roll.

During the offseason, Arenado texts video wanting feedback. But Dahl uses it as a guide.

"He'll always send me his swing and say, 'What do you think?'” Dahl said. “I'm like, 'Oh, you rake. It looks great.'”

Arenado, however, received valuable advice when he felt his swing waning during last season.

“I notice that David and [catcher] Tom Murphy always have watched me hit,” Arenado said. “I was feeling so out of whack, not myself. They told me, ‘Bro, you’re not doing the toe tap [with the left foot]. I said, ‘Really?’ I fixed it, and felt like I went off.”

The difference was subtle. It’s hard to tell the difference on video, but Dahl and Murphy picked up on a difference in his weight balance.

“Sometimes with hitting, a lot of guys have different verbiage, and sometimes things get lost,” Arenado said. “Our verbiage is the same. We talk about staying long through the baseball and finishing high, little things like that.”

Dahl, appreciating that Arenado likes his joking manner, was happy he and Murphy could help last year.

“I think he liked it,” Dahl said. “He had another good year.

“Even if he didn’t toe-tap, he’d have a good year.”

Arenado hopes all their banter leads to a big season for both. And maybe he’ll give Dahl one of his told-you-so smiles when he pulls off an opposite-field round-tripper. More importantly, he hopes to enjoy a full season of Dahl’s production.

“The confidence is there, but his work ethic is there, too,” Arenado said. “And wanting to learn the game and doing his homework is there, also.”