When Booker was at Kentucky, Herro was a thin, 14-year-old high school freshman who was taking no prisoners on the hardwood in Wisconsin. He dominated the state basketball circuit, averaging 32.9 points, 7.4 rebounds, 3.6 assists and 3.3 steals per game in his senior campaign. By that time, Booker was establishing himself in the NBA and, unbeknownst to him, as someone Herro wanted to emulate.

When Herro was being recruited by Kentucky in 2017, he would ask the coaches about Booker. Associate head coach Kenny Payne, who coached both Booker and Herro in college, can recall the moment vividly.

“One day during the recruiting process, Tyler said to me that he tried to hit Devin on Instagram or something, but he didn’t think he had responded,” Payne told NBA.com. “And from time to time, he would ask me about Devin’s past, and you could see he paid real close attention to what I was saying on what made Devin unique.

“And then once he decided to come to Kentucky, it was, ‘I’m a dog. I’m like Devin Booker.’”

In perhaps another opportunity to make his game akin to the Suns star, Herro worked out with Booker’s primary offseason trainer, Robbie Haught, before his lone season at Kentucky. Twice a day for four days straight, Haught put Herro through the same scrupulous drills that he’d do with Booker.

The resemblances stood out.

“Tyler’s a killer,” Haught told NBA.com. “They both have that same mentality, they don’t care who’s in front of them. They’re gonna get it done. I knew he was a pro when we worked out. They both take their craft as seriously as you possibly could. They both have that swag on the court. They both talk sh--. You can see why they compare them, whether it’s a fair comparison for Tyler or not. There are similarities.”

Once Herro got to Lexington, Booker began to follow his game intently. Herro displayed a sterling shot-making ability and a supreme level of confidence that anybody watching him would notice. That included Booker, who did the reaching out this time.

“I think it was on Twitter,” Herro said. “After a Kentucky game, he hit me up, said good game. And then I just got his number through there and we started talking.”

Suddenly, a bond clicked between the two. Booker talks with Herro after Heat games, shares with him the type of shots he wants him to shoot and where he needs to be.

It’s a sensei-to-grasshopper bond, except this sensei happens to be just four years older.

“He’s like a big brother to me now,” Herro said about Booker, who’s providing the Heat guard the type of guidance any first-year player would covet.

“He calls me all the time to tell me what I’m doing [on the court]. Stuff like that. He’s pretty much just a big brother to me. So our relationship is pretty close.”

In order for Herro to make the strides that his mentor has made, his work ethic must be inexorable. Booker established himself in this league a long time ago, and he’s kicked things into overdrive to start this season. He’s a bucket-getter who does it balletically on all three levels. He’s currently terrorizing opposing defenses with his efficient scoring and improved playmaking. And while an upgraded Suns roster and coaching staff deserves credit for his recent play, it’s the work Booker puts in that is fueling his separation.

That and his willpower.