In 2006 Variety interviewed Avildsen, who said that a film with a boxing story didn't excite him at first, but he was "moved by the urban character study of Sylvester Stallone's script".
Another underdog film, "The Karate Kid", was also an unexpected success at the box office and spawned a series of films, a sequel and a remake.
Rocky was nominated for 10 Oscars and won three, with Stallone taking the best actor award.
Pakistani PM to appear before court-appointed investigators
The PM's sons - Hassan Nawaz and Hussain Nawaz - have already been summoned and grilled for hours by the JIT several times in recent days.
He also had his share of career setbacks, directing some clunkers and being fired as director of 1970s classics Saturday Night Fever and Serpico because of disputes with producers.
"He was a pretty extraordinary man in my estimation. He was super talented and very driven and very stubborn and that was to his detriment but also often to his benefit", Anthony was quoted sayin to WFAA.com.
The Directors Guild of America paid tribute to Alvidsen, saying: "Throughout the decades, his rousing portrayals of victory, courage and emotion captured the hearts of generations of Americans".
Avildsen was one of the the great filmmakers, and now he is with us no more. "It's better not to be doing something you don't want to do", Avildsen told the Los Angeles Times after he departed from the project. His other films include Neighbors, The Formula, Lean on Me and For Keeps. The documentary is a companion to the book "The Films of John G. Avildsen: Rocky, The Karate Kid, and Other Underdogs", written by Larry Powell and Tom Garrett. "And the opposite would be too depressing".
Be proactive - Use the "Flag as Inappropriate" link at the upper right corner of each comment to let us know of abusive posts.