The pair have known each other since they were 12, when they raced karts together, and Hamilton has done his best to reject the popular notion that he is about to wipe the floor with his new Mercedes team-mate.
Hamilton, like every other Formula One driver, is measured first and foremost by how he performs against the other man in the garage. And as one of the three leading drivers of his generation, along with Fernando Alonso and Sebastian Vettel, Hamilton should ultimately be the faster of the two Mercedes drivers; he has won a world championship and has 21 wins from his 110 races, against Rosberg's solitary triumph in 128 attempts.
But it may not be easy. His marginally more experienced colleague – who has joint Finnish and German nationality and whose father, Keke, was 1982 world champion – is entering his fourth season with Mercedes. A fluent speaker of five languages, Rosberg also has a profound feel for the engineering side of the sport and is arguably the brightest mind on the grid. He is no pushover either; he had the better of an albeit diminished Michael Schumacher in their three years together.
Jenson Button, who scored more points than Hamilton in their three years as McLaren team-mates, has shown that speed is not everything. Hamilton, asked whether he was going to "boss" Rosberg, said: "That is not going to be the case. He is going to be massively competitive. He wants to win, he is hungry as ever and it is great to see.I need to match that.
"We played table tennis once and he beat me. He is pretty good but I am getting better." Hamilton added: "Probably the first bit of real competition we had was when Nico used to ride a unicycle everywhere. So I thought I've got to learn to ride this unicycle, I've got to be better than him. I spent all my time outside the go-kart learning to ride this unicycle. We always had great competition, whether on the racetrack or computer games or playing football.
"We always had that. It was a really good period of time in my career and in my life and I look forward to making some more great memories." According to Rosberg, it took Hamilton only two hours to master the unicycle. "We had the finest times," Hamilton recalled. "I have never laughed so much than when we were racing together. Nico was kicking everyone's butt at that time. We had some great races together and built a great relationship.
"But we are grown men now. He is almost married. You could say the same about me, probably.With his competitiveness, he wants to beat me and I'm not here to mess around. I want to do the same."
But Hamilton says he is sharing all his information with Rosberg. "When we were in testing I wrote a map on how my car was feeling that day. Nico was there and said: 'Can I have your map, please?' I said: 'No, no one has ever asked to see my map before.' But then I was like: 'Go for it.' It's transparent. He can have all my settings and vice versa."
Rosberg, too, sounds up for the battles ahead. "To be up against Lewis is one of the best experiences out there, for sure. There was always big fighting in go-karting between the two of us. We need to reduce that a little bit and focus more on the track and the driving now."
Watching how each driver drove his car to a standstill in practice on Friday afternoon in their first outing, the competition between the two should be compelling.
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