BOSTON – Jaylen Brown’s athleticism was among the many reasons the Boston Celtics selected him with the No. 3 overall pick in last month’s NBA draft. But even before he became a Green Teamer, Brown’s aspirations were much greater than being a high draft pick.

“I want to be a top five player in the league,” Brown said at his introductory press conference last month. It’s a lofty goal for sure; the kind that requires more than just talent. And that’s where Graham Betchart – Brown’s mental skills coach - comes in.

Betchart’s work as a mental skills coach has been on full display as one of the keys to Brown being among the standout performers during summer leagues in both Salt Lake City and Las Vegas, respectively.

The 6-foot-7 rookie was named to the Las Vegas Summer League’s second team, one of just three lottery picks (top-14) in last month’s NBA draft (Ben Simmons of LSU and Thon Maker of Milwaukee) named to the first (Simmons) or second (Maker) team along with Brown.

In addition to Brown, Betchart has worked with each of the last three first overall picks – Andrew Wiggins, Karl Anthony-Towns and most recently, Simmons. Betchart said he also worked with current Celtic guard Marcus Smart when he was at Oklahoma State.

While each player has their own specific program, there are some common threads that bind all of his clients.

“The big thing I want them to focus on is what in their control,” Betchart told CSNNE.com from New York City where he was meeting with the New York Jets wide receiver Brandon Marshall, who has been one of the more outspoken athletes when it comes to mental health-related issues. “And so for a lot of these guys, they’re so good in high school and even college, they can focus on results and still produce results. As you get older, you realize that results are totally out of your control. And so my focus is getting them to focus on what’s in their control, and learning how to do it consistently; how to create a pattern, a consistent mindset.”

We saw that from Brown this summer with the Celtics’ summer league teams. He averaged 16.0 points and 6.2 rebounds but did so shooting a not-so-great 30.7 percent from the field and was even worst (27.2 percent) on 3s.

However, he did manage to get to the free throw line 10.2 times per game, which is surprising when you consider whistles typically aren’t blown as often in the summer than they are in a regular season game. And just to put his free throw average in perspective, only two players – Houston’s James Harden and Sacramento’s DeMarcus Cousins – averaged more than 10 free throw attempts per game last season.

Brown has said on more than one occasion that getting to the free throw line often has to be one of his strengths in the NBA. Based on what he did this past summer, there’s no question it’s something he has indeed made a priority.

And the fact that Brown was able to do it consistently this summer falls in line with one of the core concepts that Betchart preaches to his clients.

“To me the hardest thing in sports is to be consistent,” said Betchart, who is now the director of mental training for San Francisco-based Lucid, a mental training app for athletes. “Anyone can just once in a while show up and have a great game. It really starts with having a consistent mindset based on what you can control. They have to be in the moment no matter what’s going on. It could be really bad, it could be really good.”

And when it’s over, players can’t dwell in the mistakes of the past.

“We make a mistake and get hung up sometimes,” Betchart said. “But if you can move on to that next play and train your focus to do that, it’s really hard to stop you if you don’t stop yourself.”

Instead, those mistakes actually form the foundation for future success.

In the case of Brown, one of the biggest knocks on him coming into the NBA was his shooting touch being anything but consistent.

“It’s the growth mindset,” Betchart said. “If you are going to master shooting, you’re gonna have to miss a lot of shots. It’s kind of like learning to walk. When you were learning to walk, you don’t remember but you fell down all the time. You didn’t say, ‘Oh I’m not going to walk. I’m just going to stay on the ground.’ You just picked yourself up and eventually you learned. When you get to the professional level, your game is analyzed on where it is right now. And right now, he’s 19 years old. There’s no way he’s going to be as good a shooter now as he’ll be at 23 and 25. And so if he embraces the growth mindset and just continues to focus on his process, which is taking the shot, being assertive, taking your shot, it’s all going to work out. I know this to be factually true.”

Another one of Betchart’s clients is Orlando forward Aaron Gordon, who came into the NBA as one of the worst free throw shooters in college basketball. In his lone season at Arizona, Gordon shot just 42.2 percent from the free throw line.

In his two NBA seasons, the 6-foot-9 forward has shot 68.1 percent.

“People were laughing at (Gordon’s free throw shooting) sarcastically and now as a pro he’s shooting (almost) 70 percent,” Betchart said. “It was all based on a growth mindset; just allowing yourself to fail and really, you’re not failing. You’re learning how to shoot. We introduce a concept called Victory goes to the Vulnerable. You’re going to be vulnerable sometimes. People are going to talk about your shot. That’s OK. We let people have their opinions. We don’t try and stop them. It’s all part of the process.”

Ah yes, the process.

If you listen to Brown, he has said on more than one occasion whether he played well or not, that all that he’s going through now is part of a process that will eventually make him a better person and a better player for the Celtics.

Part of that process is utilizing the various mental techniques and teachings of Betchart, who has known Brown since he was 15 years old and had a chance to spend a considerable amount of face-to-face time with him this past year when Brown was at Cal.

Most of what Betchart talks about has a strong basketball teaching component to it. But at the end of the day, there’s a lot more going on.

“Everybody starts to realize these are life skills,” Betchart said. “It’s tough to separate basketball from life. You’re going to be who you are on the court, off the court. These skills, learning to control what you can control, being present, moving on after mistakes, this is what we leave in life as well, learning how to be vulnerable in life and do those things. It naturally gravitates towards life and … what’s going on in life. It’s a natural progression. They’re human beings who choose to play a sport for a living. They are not basketball players; Basketball is what they do.”

A. Sherrod Blakely can be followed on Twitter: @SherrodbCSN