James Packer and Lachlan Murdoch toasted the "death" of Fairfax with glasses of vodka, the author of a new book on the decline of the news outlet says.
Speaking at the launch of her book Killing Fairfax, Australian Financial Review journalist Pamela Williams said the moguls were trained from birth to stalk the embattled media company.
Mr Murdoch and Mr Packer had "primal vendettas built into their DNA and life experience", she said.
"James Packer and Lachlan Murdoch ... stalked Fairfax's business," Ms Williams said on Tuesday.
"I think they were both trained to hunt from birth."
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Ms Williams told the launch - attended by both Mr Packer and Mr Murdoch as well as numerous high-profile journalists - that Fairfax once dominated the classifieds market.
But she said Mr Murdoch and Mr Packer were able to "get behind" websites like seek.com.au, real estate.com.au and carsales.com.au to take market share from Fairfax.
Ms Williams recalled a lunch she attended at which Mr Murdoch and Mr Packer raised a toast over vodka to "killing" the iconic media company.
"James said 'I think we killed Fairfax', and Lachlan said 'I think so, too', and they clinked their glasses."
Fairfax in July introduced paywalls for its Sydney Morning Herald and The Age websites to try to reverse sharp falls in revenue.
In June 2012, the company said 1900 jobs would be cut over three years as it moves to become a digital media company.
Speaking to reporters, Mr Murdoch said media companies had to continually reinvent themselves, "particularly in a time of rapid change".
He said his age had nothing to do with his success in the sector.
"I think you just have to be young at heart," Mr Murdoch said.
Business Spectator chief editor Alan Kohler, who launched the book, labelled what had happened to Fairfax "a tragedy".
He said the company had been mismanaged by its board of directors.
"The main job of a board is to smell the smoke coming under the door; well the Fairfax board couldn't see each other through the smoke, and they still couldn't smell it," he said.
