In the fourth, he punished any Celtics defender who hoped to stop him. With just under four minutes remaining and Al Horford guarding him, Beasley pulled back to hit a step-back jump shot to give the Knicks a 91-81 lead.
It was an extraordinary run for Beasley. With Tim Hardaway Jr. out because of an injured left foot and Kristaps Porzingis mostly ineffective as he returned from a knee injury, Beasley gave the Knicks everything they needed.
He heard “M-V-P” chants multiple times during the fourth quarter. Almost single-handedly, Beasley propelled the Knicks to a victory over the team with the third-best record in the league and an actual M.V.P. candidate in Kyrie Irving.
It was Beasley’s third 30-plus-point game this season, despite averaging just over 17 minutes per game. He also scored 30 points Saturday night, outdueling Carmelo Anthony in his return to the Garden.
“I see it every day,” Courtney Lee said. “I’ve been playing against Beas for 10 years. I know what he’s capable of doing. I don’t know what it is — if I had to rank top scorers in the league, he’s top-five up there, man. He’s inside and outside with it, with touch, finishing with both hands.”
The Knicks were desperate for heroes Thursday because Porzingis was uncharacteristically quiet. He missed all 11 shots from the field and was held to a single third-quarter free throw. It was the worst game of his two-plus N.B.A. seasons. The Celtics hounded him with smaller defenders and tried to bruise him with Horford and Aron Baynes. His troubles were compounded by misfortune as he missed several open shots.
For a half, the Knicks were able to overcome those deficiencies. They held a 44-40 halftime lead as the teams looked as if they were hitting the court after long naps. The Celtics, on the second night of back-to-back games, hit only 34.9 percent of their shots before intermission, relying on Irving’s brilliance to keep them close. He finished with 32 points despite missing 15 of 27 shots.
Enter Beasley. He claimed this night was no different than any other — that his skills have never wavered even if it seemed to everyone else that his scoring took off in the second half. He has felt like he has been playing with a hot shooting hand for a while — since, he said, “January 9, 1989,” his birthday.