BOSTON -- The outcome was clearly not in doubt, so it was OK for the TD Garden crowd to be cheering for someone on the other team.
Devin Booker did not disappoint.
The 20-year-old super kid from Kentucky scored 28 of his 70 points in the fourth quarter, 18 in the final 3:46 as his team called timeouts and committed fouls to stop the clock.
"It's a zone. It'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."
It was the most points ever scored against the Celtics, the most points ever scored in either of the Boston side-by-side buildings and tied for the 10th-most points in NBA history. He joined Wilt Chamberlain (six times), Kobe Bryant, David Thompson, Elgin Baylor, and David Robinson as the only 70-point scorers in league history -- and he shattered Tom Chambers' 27-year-old (to the day) club record of 60.
Booker, whose previous career high was 39, went 21 of 40 from the floor, 4 of 11 from 3-point range, canned 24 of his 26 free throws and also had eight rebounds and six assists.
"When you're in the gym alone and you're taking shots, you're making them consecutively," he said. "That's what it started feeling like. I felt comfortable. I was at my home gym training. It started getting easier and easier. Shots just kept falling -- tough shots, too."
He said he once scored 56 points in a high school game, "but not anything close since then."
"It was weird what they were doing," he said. "I've never seen anything like that. It is what it is. I don't think anybody has ever seen that; continuing to call timeouts, continuing to foul when we were up 15, but I mean it was obvious what they were trying to do."
Said Watson: "Calling timeouts at the end kept the game close. It's basketball. I'm not coming to any arena to be liked. If people don't like us while we build ... so what, do something about it."
Thomas, a former Sun, said he didn't "want to get into" any possible disrespect for the game, but added, "We're worried about the playoffs, they're worried about the lottery."
As far as getting cheered away from home, Booker said, "That meant a lot, especially here in Boston. I know how rowdy they can be on opponents sometimes. I respect that. That's how it should be.
"It's a night I'm going to remember the rest of my life."
"Obviously, he got it going," said Celtics coach Brad Stevens, who was coaching his players hard on defense down the stretch. "And he's a really good player. I thought no matter who we tried on him, what we tried on him, he was in one of those zones in a rhythm."
The undermanned Suns lost their seventh in a row and their ninth in 10 games since beating the Celtics in dramatic fashion in Phoenix March 5.
Alan Williams had nine points and 14 rebounds for the Suns.
The win, the Celtics' third straight in the first three games of a six-game homestand, was their 13th in their last 14 home games and the fifth win in their last six games overall.
The Celtics (47-26) held the Suns (22-51) without a field goal for the first 7:15, building a 22-3 lead before settling for a 13-point advantage after the first quarter. They never trailed.
NOTES: Celtics G Avery Bradley was hospitalized with a stomach bug to receive fluids and missed the game. ... The Suns were without F T.J. Warren (wrist). G Eric Bledsoe, G Brandon Knight and C Tyson Chandler were all "resting." ... It was the second straight night the Suns fashioned the youngest starting lineup in NBA history, a group younger that seven of the eight NCAA starting lineups from Thursday night. ... F Marquese Chriss and G Tyler Ulis became the first Phoenix rookie pair with double-doubles in the same game since 1991 in the loss at Brooklyn on Thursday night. ... G Isaiah Thomas extended his club record with a 3-pointer in his 47th straight game. ... The Celtics are 21-0 when leading after three quarters at home. ... The Suns visit Charlotte and the Celtics host Miami on Sunday. ... Suns coach Earl Watson said he had wagers between himself and four Kentucky players for the Kentucky-UCLA Sweet 16 game.