Newton said his mother, Lisa Brown, had been ill for about three years.
"My mom was great," he said. "She was real blunt, would tell it to you like she saw it. She would joke a lot, too."
Newton, the Catholic League's most valuable player, produced a go-ahead field goal and then went 4 for 4 from the free-throw line in the extra session.
"It's one of the most amazing things I've ever been a part of," Arrigale said. "He handled it better than me. I don't know how I would have handled it if that happened to me when I was 18 years old."
Thursday, only hours after his mother's death, Newton chose to practice with his teammates.
"It was probably the best thing for him," Arrigale said earlier Friday. "I'm sure it served as a distraction. We're like his second family."
Against Susquehanna Township, Newton shot 11 for 19 from the field - 5 for 9 on three-pointers - and 6 for 8 from the line. He added eight rebounds, two steals, and a blocked shot in 35 minutes.
Arrigale visited Newton at his home Thursday. Seniors Jamal Custis and Troy Harper were already there offering condolences.
When Arrigale, Custis, and Harper were leaving for afternoon practice, Newton was right behind them.
"I was like, 'What are you doing?' " Arrigale said. "He said, 'What do you mean? I'm coming to practice.' "
Neumann-Goretti (27-4) closed the season with 17 straight victories. Its last loss came against Catholic League rival Roman Catholic on Jan. 23 at Philadelphia University.
En route to 13 first-half points, Newton shot 5 for 8 from the field, including 3 for 4 from three-point territory.
Junior forward Quintin Ward and Nehemiah "Bud" Mack paced Susquehanna Township (23-8) with 18 and 16 points, respectively.
Neumann.-Goretti 12 14 21 6 11 - 64
Susquehanna Twp. 13 13 18 9 4 - 57
NG: Lamarr Kimble 10, Troy Harper 12, Tony Toplyn 5, Jamal Custis 4, Ja'Quan Newton 33.
ST: Nehemiah Mack 16, Gabe Mack 11, Joe Marshall 5, Quintin Ward 18, Takhi Turner 5, Ayan Penn 2.