Turning 50 last year, Italian director Paolo Sorrentino found he was finally ready to put his heartbreaking story about growing up in 1980s Naples on film, in all its exuberance and anguish.

The Hand of God is an autobiographical film that explores family, maturity, and a moment in time when the chaotic underdog city gained dignity and hope with the arrival of football legend Diego Maradona. 

"At a certain point, you take stock of the beautiful things that you've loved in your life," the director told journalists ahead of the film's premiere at the Venice Film Festival on Thursday. 

Renowned for his Oscar-winning The Great Beauty and Netflix hit The Young Pope, Sorrentino said he was partly provoked by a friend who accused him of avoiding personal films.  

"I realised there was a lot of love in my boyhood, even though one part was painful, and that all this could be told cinematographically," he said.

If The Great Beauty was an ode to Rome, his latest is similarly a love letter to his hometown.

"Naples in the '80s was like going on a safari on foot without the safety of a jeep," Sorrentino said. 

"It was very fun, very violent, very dangerous. It was like a jungle – you could meet a lion but you could also meet beautiful birds."

What every Neapolitan of that era remembers is the arrival of Argentine legend Maradona to play for the struggling local team.

"For me as a boy, the most important thing that happened at that time was the fact that Maradona came to Naples," Sorrentino said. 

The film's title refers to Maradona's infamous handball goal against England in the 1986 World Cup. 

It traces how the young Sorrentino, represented by alter-ego Fabietto (played by newcomer Filippo Scotti), was indirectly saved by the footballer, before he went on to pursue his dream of becoming a filmmaker. 

"The message of the movie is that there is a future for everyone, regardless of the suffering and the pain you have experienced in life," he said. 

"I hope that young people can understand this because... they're more worried about the future than we were."