This one-and-done thing the past 12 years has produced mixed results, with some players flourish into All-Stars while others fall to the wayside.
Devin Booker matter-of-factly declared for the draft after averaging 10 points in his lone season at Kentucky — as a reserve. And he slipped to the 13th pick in 2015 because those before him had more accomplished college careers or more gaudy numbers or more physical potential.
Nearly two years later, Booker is a franchise cornerstone with the Phoenix Suns. The smooth shooting guard, one of the faces of the NBA future, put on scoring clinic Friday at TD Garden.
His downtrodden team, with its infantile starting lineup that averaged 21 years — younger than most Sweet 16 rosters — trailed by double digits most of the night. Meanwhile, Booker made scoring history.
Booker, all 20 years of him, scored 70 points in the Suns’ 130-120 loss to the Celtics.
Seventy.
It was the most ever scored against the Celtics and the most points in the Suns’ 49-year history. It was such a surreal night that Al McCoy, the Suns’ 83-year-old play-by-play man, was left marveling. He reminded Booker that exactly 27 years ago — March 24, 1990 — Tom Chambers set the club record with 60 points.
Booker is a prime example of the unpredictability of the NBA Draft. He fell to 13th and yet is averaging the second-most points from his draft class — t0 No. 1 overall pick Minnesota’s Karl-Anthony Towns.
His ascension has been hidden in the desert because the Suns have been putrid. But what Booker displayed Friday night was indeed a treat for a Celtics faithful that likely couldn’t name three Phoenix Suns. By the end, when it was apparent the Celtics were going to win the game, the crowd sensed history and cheered as Booker approached 70.
While the Celtics were rather upset Phoenix coach Earl Watson called two timeouts in the final minute to get Booker more scoring chances, they have to just be resigned to the fact nights like these happen, even against the best of teams and best of defenses.
Booker scored 51 points in the second half, when he attempted 21 free throws and 26 of the team’s 46 shots.
“It’s a zone that’s kind of hard to explain,” Booker said. “I’ve been in those zones before but never to this extent. It’s hard to explain. When you’re in the gym alone and you’re taking shots and you’re making them consecutively, that’s what it started feeling like for me. It was comfortable and I was at my home gym training. It started getting easier, and shots just kept falling, tough shots.”
The funny thing is Booker said he kept hearing Celtics coach Brad Stevens angrily yelling at his defense how many points Booker had. He scored 23 in the third quarter to get to 52, but the Suns still trailed by 17. He just kept shooting in the fourth and passed 50, then 60, while Watson, the 37-year-old coach, kept pushing his pupil to score.
The Suns are building for the future and on most nights they don’t make national headlines. Watson wasn’t going let this opportunity pass.
“He wants to be one of the best players in this game and he’s only 20 — 70 points was legendary,” Watson said. “He earned it the toughest way.”
Watson then became emotional when asked about calling those two timeouts in the final minute. The second-year coach is fighting for respect. If you recall, the Celtics took the Suns for granted earlier this month and lost on a buzzer-beater.
Maybe the same would occur Friday, so Watson made sure Booker could score as many points as possible. It perhaps wasn’t appreciated in the Celtics’ locker room. But isn’t the point of professional sports to score as many points as possible?
“I’m not coming to any arena just happy to be there and be liked,” Watson said. “I don’t care about being liked. I really don’t care to be honest with you.
“We’re coming in here trying to build something with this young group. People don’t like us while we build it? So what? Do something about it. Simple as that. It’s about letting our kids be great. You got a problem with it? Do something.”
It’s the right attitude for an organization seeking respect. Booker is the central figure of this rebuilding plan, a message to the rest of the league that draft gems can be found in the teens.
“The Celtics won the game,” McCoy said. “But it was Devin Booker’s night.”
Boston will move on, improve as the playoffs approach, and shake off the embarrassment of home fans cheering for a visiting player. It was surreal and somewhat uncomfortable, but it was history and that has to be acknowledged and respected.
Booker wasn’t even born when TD Garden opened. He is part of the NBA’s bright future, the same age as Jaylen Brown. So there should be nothing but positives taken away from Friday, and a lesson to the Celtics that they don’t need the highest pick to nab the most outstanding player.
Gary Washburn can be reached at gwashburn@globe.com. Follow him on Twitter @GwashburnGlobe.