Lewis Hamilton and Nico Rosberg's friendship faded in the face of F1's intense pressure
Rosberg retired as F1 World Drivers’ Champion at the end of last season, having beaten Lewis Hamilton by just five points.
The Mercedes team-mates had fought three consecutive bitter title races with Hamilton triumphing in 2014 and 2015 before the German got his maiden win in 2016.
The battles had sour their friendship which had started when they were both stars of the karting circuit and the Brit claims he got the upper hand when they first started racing.
Hamilton throws steering wheel after crash with Rosberg Sun, May 15, 2016
Lewis Hamilton throws his steering wheel in frustration after colliding with Nico Rosberg on the first lap of the Spanish Grand Prix
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Mercedes' Lewis Hamilton fails to control his temper after colliding with teammate Nico Rosberg on the first lap of the Spanish Grand Prix, and throws his steering wheel out of the car
“I went to Europe to race in Italy when I was 13 and at the time Nico was the golden child there,” Hamilton told Sky Sports.
“He was in a works team and he was known as an ex-world champion’s son so the spotlight was all on him.
“He had a target on his back.
“Our first race together was at a place called Parma and we were first and second for the whole 23 laps.
“In karting, you push the karts and draft to get away from the rest and in the last lap I overtook him and won the race.
“He took it amazingly well and that was when our friendship started.”
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Nico Rosberg sealed a maiden world title last year and then retired
The two drivers were team-mates in junior formulae and were reunited at Mercedes in 2013 in what appeared to be a dream line-up.
But Rosberg claimed when he retired that it was destined for failure on a personal level.
"We were best friends 15 years ago and, for sure, I still have that base respect, even if it has difficult moments," Rosberg said.
"And the environment means you can't be friends.
“We're just fierce rivals and fighting it out there for the championship all the time, you can't be friends.
“As long as one guy doesn't accept 'ok, you're better, I'll be second' you can't be friends – it's just difficult."