I'm not sure if there was a character named Larry Novak in 'A Christmas Story'. I don't recall such a name from the movie. It could be a relatively minor character or perhaps not in the movie at all.
Novak Djokovic is a Serbian tennis superstar. He has had an incredibly successful career. He's known for his amazing skills on the court, especially his powerful groundstrokes and great agility. He has won numerous Grand Slam titles, competing fiercely against the likes of Roger Federer and Rafael Nadal. His journey in tennis started at a young age and he has continuously worked on improving his game over the years.
It's hard to say exactly who Larry Novak is without more context. He could be a central figure with a key role in the plot or just a minor character who adds some flavor to the story.