Sebastian Mack drove down the left side of the court, weaved to the opposite end and pulled up from 30 feet.

He sank it.

Mack defeated rival Henderson (Nev.) Liberty at the buzzer. Right after Liberty tied it at 55-55 with five seconds left, Henderson (Nev.) Coronado coach, Jeff Kaufman, held his timeout, wanting his senior guard to get the ball and go.

"We were all celebrating, and I looked over and he ran down their bench," Kaufman laughed. "It's not a great sportsmanship thing, but this was our rival school. It was a Tarkanian tournament. It was to advance to the final. That's just the guy he was, man. We're all celebrating, and he's proving his point, flexing his muscles."

Mack was fiercely loyal to his Coronado teammates. He brought a strong locker room presence and defended every player in the same uniform as him.

"I'm making him sound like he's a bully or something. He's not," Kaufman said. "He's just got that mentality where he looks you in the eye and you know that he's serious."

Hailing from Chicago, Mack quickly showed his toughness when he moved to Nevada. He began his high school career at Las Vegas (Nev.) Durango before transferring for his junior and senior seasons. Kaufman previously coached Chicago products, but Mack boasted another level of confidence on the court compared to past players.

"If you get in a fight, he's the guy you want on your side fighting with you," Kaufman said. "He's relentless, not that he's dirty or nasty or anything like that. When it comes to wanting to win and when it comes to wanting to play hard, he is a no nonsense kind of player."

That reflected in Mack's time at UCLA.

Before announcing his transfer commitment to Missouri on Monday, Mack played two seasons for the Bruins. Opponents didn't always want to be around him because of his physicality, boasting a knack for rebounding as a guard and running downhill at opponents on both offense and defense.

"He'll just go through a building," Kaufman said. "It's really just his mentality about how he approaches life, and sometimes it's good, sometimes it's bad, but for the most part, it's very good. He's all around a good person."

Knowing Mick Cronin for years, Kaufman got the UCLA coach on campus to see Mack play. Mack set the tone early with a strong performance against powerhouse Montverde (Fla.) Academy and became a top target for the Bruins.

In his freshman season at UCLA, Mack started 30 games, but he wasn't supposed to.

Kaufman told his former player numerous times that he had a lot to learn, but with a twist of fate, one that featured roster complications, Mack was third in scoring for the Bruins his freshman year.

"That's not how that was supposed to work," Kaufman said. "It's UCLA for God's sake. ... Now, you're in a situation to take advantage of it, and he did. The fans really liked Sebastian out there, and he did what he was supposed to do. And he came through."

UCLA built up its team more through the transfer portal ahead of this past season. Mack embraced a new role coming off the bench, and even in times of needing a score late, the sophomore was always on the court.

Mack received interest from Florida State in high school, and although Missouri coach Dennis Gates was removed from his time on the Seminoles' staff, that coaching tree played a part in Mack's decision in the transfer portal.

"I think it's the right guy for him," Kaufman said. "Sebastian needs a certain kind of coach. I really think he does. Somebody that can be tough with him but yet understand him. And I think that Gates does that. I think Cronin did that, too. ... Sebastian needs a little conflict every now and then. He needs to be driven."

Entering his junior season, Mack received a push for professionalism from Kaufman. His former coach preached being first to workouts, staying late and doing the extra things. With those goals, Kaufman predicted Mack will thrive with more freedom in the Tigers' system.

"If you want to continue your career, it's going to be necessary," Kaufman said. "Sebastian has always been good about that, but I feel now it's very, very important for him. ... It all starts his work ethic, his professionalism, and he's committed to bringing that to Missouri."

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