Austin Rivers had been shooting like a rookie. In a five-game stretch, Rivers, a rookie guard for the New Orleans Hornets, made just one basket: a free throw. He was 0 for 9 from the field.

The way Rivers walks, smiles, and interacts with NBA veterans with overflowing confidence, it can be easy to forget that he’s only 20 years old. And until Wednesday, his father, Celtics coach Doc Rivers, had never seen him play an NBA game in person.