Such a special night for him and the whole organization,” said Flagg, who turned 19 in December. “Cooper, he played like the best player we’ve played all season,” said Knueppel, who set a franchise rookie record hitting eight 3-pointers. Cooper Flagg, who scored 49 points, drives to the basket during the Mavericks’ home loss to the Hornets. “Just having fun.”The two leading candidates for Rookie of the Year finished the night with Flagg averaging 19.5 points per game, Knueppel 18.9. “We’ll both be looking back on this night and this whole year in general the rest of our lives,” Flagg said.