Best Of Frenemies: How Lewis Hamilton and Nico Rosberg went from best buddies to feuding team-mates

Back in the early years of their careers, they were best friends and room-mates. Yes, they were competitors in their early careers, but it was a rivalry that never threatened their friendship.

"I have never laughed so much than when we were racing together," Hamilton told the BBC.

"We had some great races together and built a great relationship. We were just arriving and enjoying go-karts and eating pizzas every weekend, fighting all the time and just having fun."

Robert Kubica was also friends with the pair at the time.

"They always wanted to win, to beat each other," he said.

"But they didn't fight. It was friendly competition. There was always laughing afterwards. We had so much fun. We were friends. It was nice. We were normal kids. I have good memories of growing up with them."

Hamilton added that the two were so close that they even talked as teenagers about driving together in F1 one day.

"We were talking about how cool it would be, one day, if we were in Formula 1, just how cool it could be to be team-mates," Hamilton said. "We said it several times.”

How different things look now. Hamilton and Rosberg, the teenage friends, whose trouble with each other only began when they ended up on the same Mercedes Formula One team.

It didn't take long for the first cracks to appear. In March 2013, at the Malaysian Grand Prix, Rosberg was ordered not to overtake Hamilton, with the German ending up in fourth.

Team boss Ross Brawn later insisted that it was due to fuel strategy, but Rosberg was still desperately unhappy not to be allowed to pass his slower colleague - despite Hamilton sympathising publicly, and calling Rosberg a "great team-mate".

"If I'm honest I feel Nico should be standing here. He had better pace through the race. Nico deserved to be where I am. Would I let him past in the future? I probably would."

Those words couldn't ring more hollow now. At Hungary this season Hamilton had a chance to repay the favour when Mercedes orderered him to let Rosberg through into third place.

What did Hamilton do? Fuming, he outright refused, blocking the much faster Rosberg - who could yet have challenged for a race win - to force the German down into fourth palce and claim third for himself.

Rosberg got his own back just a few weeks later - and in style, as a bitter season came to a head in the Belgian Grand Prix at Spa Francorchamps. Rosberg deliberately took Hamilton out as the pair entered a corner together, getting punished by Mercedes for an act of out-and-out petulance.

"Nico hit me. Nico's hit me," Hamilton said.

Rosberg said sorry later - though in the most perfunctory terms: "I have already expressed my regret about the incident but, after meeting with Toto, Paddy and Lewis today, I wish to go a step further and describe it as an error of judgement on my part. For that error of judgement, I apologise to Lewis and the team.”

And Hamilton was not mollified: "We had a meeting about it and he basically said he did it on purpose. He said he could have avoided it, but he didn't want to. He basically said, 'I did it to prove a point'."

At the time Rosberg was leading the standings, but thereafter Hamilton took charge of the race for the title - and he admits that his righteous indignation fired him up.

"Spa was like, 'I'm going to turn this up. I'm going to have to turn this up," he said earlier this season.

"'This means war', that kind of feeling. I took that energy and turned that negative bomb into a positive."

Any friendship is gone forever, from the sounds of things.

"Nico and I can count our friends on one hand," Hamilton said in Bahrain.

"Nico does not come into those five friends I have, and I don't come in the five friends he has."

But the rift is deeper than that. Whatever happens on Sunday afternoon, the pair are already firmly established in the history of F1's feuding team-mates.