Lewis Hamilton suggests Mercedes Formula 1 team-mate Nico Rosberg lacks the hunger he has to win the world championship because of his privileged upbringing.
As the rivalry between the pair heats up amid their title battle, Hamilton believes that the struggles he faced in his childhood to prove his talent have made him more motivated for success.
In an interview published on the official Formula 1 website, Hamilton said: "Let me tell you this: I come from a not-great place in Stevenage and lived on a couch in my dad's apartment - and Nico grew up in Monaco with jets and hotels and boats and all these kind of things - so the hunger is different.
"I want to be the hungriest guy in the cockpit from all 22 of us - even if every driver has to believe that he's the hungriest - because if I were to come here believing that Nico is hungrier than me then I might as well go home.
"So I've got to be the hungriest - to win the world championship you need to be the hungriest."
Although Hamilton and Rosberg have a long experience of racing against each other - and were team-mates in karting - a fight for the world title was always expected to affect their relationship.
Hamilton is adamant, however, that there will never be animosity between them.
"When you're so competitive it is impossible to be best friends - but then it stays respectful," he said.
"We will always have the years in karting, that kind of foundation of a long time ago..."