All NBA rookies have welcome-to-the-NBA rites of passage.

It could be taking orders from veteran teammates, facing their idols, or getting cooked by opposing veterans in games.

Phoenix Suns rookie Ryan Dunn got a dose of the latter two during the team's first three preseason games, guarding LeBron James and Detroit's rising star Cade Cunningham.

In Phoenix's 109-91 preseason home loss to Detroit on Friday, Dunn got his first start to replace the injured Devin Booker (right ankle soreness).

“It was fun,” Dunn said after the game. “Came out and it was a good crowd, so excited. Of course, we got the loss, but it was just a good experience coming out starting, getting that kind of luck from the beginning.”

However, the game became Dunn's second welcome-to-the-NBA moment against Cunningham. The Pistons' 2021 top overall pick shined with game highs of 25 points (10-of-16 shooting), 12 boards, nine assists and two steals.

Dunn had five points, struggled on 1-of-6 shooting (his only field goal was from beyond the arc), added four rebounds, a game-high two blocks and one steal in 21 minutes.

“They have a lot of great young players," Dunn said. "Cade, just the way he moves and his size, it’s hard for a good defense, especially on pick and rolls.

"He can just manipulate the defense, so that was a tough matchup for me. I give all respect to him. He’s a great player. That’s one I look up to offensively as well.”

Cunningham is a 6-6 seasoned veteran who's packed on muscle to his 220-pound frame over the past year. He's the leader of a young, highly physical Pistons team, though they lost an NBA-record 28 straight last season under former Suns coach Monty Williams.

Dunn said during the Suns' Friday shootaround his first "welcome to the NBA" moment was defending against his "childhood hero" and "GOAT" James in their 118-114 preseason-opening win over the Los Angeles Lakers in Palm Desert, California, last Sunday. Dunn (nine points including two 3s, three rebounds, one steal and an assist, plus-11 in 24 minutes) said he did "pretty well" against James, who scored 19 in 16 minutes.

There's a learning curve for all rookies in the preseason. Suns coach Mike Budenholzer understands the value in throwing Dunn into the fire as a starter opposite the Pistons' top facilitator and leading scorer.

“Ryan loves the challenge of guarding the best players, and taking the challenge whether he comes off the bench the first couple games or as a starter tonight," Budenholzer said after Friday's game. "I think Ryan can be better, we can be better, but Cade is a great young player and he showed it tonight. So it’s a great learning experience for Ryan."

The 6-7 Dunn's draft profile was largely based on his defensive strengths and 7-foot wingspan, not what he brings on offense. But in his first two games, Dunn shot a combined 6-of-13, (5-of-11 from 3); last season at Virginia he hit only 7 of 35 from deep.

Dunn exemplified his defensive prowess against the Pistons on a chase-down block on Tobias Harris' fast-break dunk attempt in the third quarter, which led to a triple by Kevin Durant in transition.

“Just keep competing," Dunn said Friday. "My shot wasn’t falling today, but I just kind of had my mentality now to just keep learning to fly around regardless, but make it up on the other end.

"I think that block helped a lot for me just getting back on defense and it’d be a good stop.”

Dunn said at Friday's shootaround it was a "full-circle moment" against Cunningham from their high school days playing for national powerhouses Oak Hill Academy and Montverde Academy, respectively.

“I actually played Cade in high school when he was on Montverde, and we got smacked when he won the championship at home. It’s cool, a full-circle moment guarding him again. But he’s one guy I love I want to watch and learn from.”

Dunn should see more time in Sunday's preseason game at Denver.

Budenholzer said at the Suns' practice Saturday that Booker will be out again, as well Grayson Allen (Achilles) and starting center Jusuf Nurkic (finger).

“It’s huge. It’s a good opportunity for (Dunn)," Suns guard Tyus Jones said. "Even though it is a preseason game, it’s still a good opportunity to experience.

"The most valuable thing is the reps and being out there on the court, getting the minutes and getting those live looks.”

This article originally appeared on Arizona Republic: Suns' Ryan Dunn has 'welcome to NBA' moments vs. LeBron, Cunningham