Berlinale film charts Boris Becker's career from 'boom boom' to bust

The career of Boris Becker, whose thunderous delivery earned him the nickname "Boom Boom" as a young tennis player, took him from the greatest heights of sporting achievement aged 17 to prison at 54, and he is unsure if it could have gone any other way.

"It's very difficult to win Wimbledon at 17," the German former tennis champion said ahead of the premiere on Sunday at the Berlin Film Festival of a documentary on his life.

"You have to be a bit crazy to cross the line and do things nobody else has ever achieved before."

One of the greatest tennis players in history who won six Grand Slam titles, Becker's on-court brilliance was matched by an inability to manage his affairs off it, that saw him pile up personal disasters from sleeping pill addictions to a prison sentence.

"You expect world champions in a sport to be like everyone else but we aren't," he told a news conference. "To have that mindset … in real life that's a problem."

Alex Gibney's Boom! Boom! The World vs. Boris Becker is the work of an unashamed fan, blending court highlights with interviews with a stellar cast of tennis greats, including current number one Novak Djokovic, Ion Tiriac, the Romanian who discovered him, and rivals John McEnroe and Bjorn Borg.

"What I liked about Boris is that unlike many athletes he is a great storyteller," Gibney said. To convey that sense of drama he envisioned the film as a "docu-western", he said, setting match points to the music of Ennio Morricone.

The last interview was conducted two days before a London court sent him to prison last April for concealing assets from his bankruptcy proceedings. "I didn't know what the rest of my life would look like," said Becker, who served eight months of a two-year term.

Becker, a self-described film fan with a weakness for bad-boy actors such as Sean Penn, Jack Nicholson and Marlon Brando, could hardly hide his glee at moonlighting as a film star but confessed he could no longer hit the ball as he once could.

"I played it very physically and had many injuries. I can't say how many parts of my body have been replaced," said the erstwhile king of the powerful serve. "Life as a tennis-winning machine is a lot harder than it looks."

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