"Nico hit me. Nico's hit me," says Lewis Hamilton calmly over the team radio, disbelief almost shading into resignation.
Hamilton's left rear tyre begins to deflate as the razor-sharp carbon fibre shards from Rosberg's shattering front wing scythe through the rubber, all but ending the Briton's race as his Mercedes is swallowed up by the chasing pack.
Hamilton, fuming afterwards, tells the press: "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'."
Hamilton and Rosberg's relationship was already strained before the second lap of the Belgian Grand Prix in August. Especially after Rosberg's qualifying mistake in Monaco three weeks earlier that angered Hamilton, as the knock-on effect compromised his own lap.
In Hamilton's eyes, the race in Belgium proved to be a turning point. "Spa was like, 'I'm going to turn this up. I'm going to have to turn this up. This means war', that kind of feeling. I took that energy and turned that negative bomb into a positive."
When two sides go to war there's always sadness. But war between two childhood friends? Who raced together as 14-year-olds, roomed together, and dreamed of a life in Formula 1 fighting for the title together as team-mates... how did it get to this?
Rewind: It's a beautiful summer's evening in Parma, Italy in 2000. Hamilton and Rosberg, team-mates at Team MBM in the Formula A karting championship, are sitting opposite each other at a pizza restaurant.
The waiter brings over two pizzas, then returns shortly after with a second for both young men. The pair look at each other, then down at the pizza, then start shovelling it into their mouths.
"As a kid, I didn't like pizza, but I remember often going out for dinner with Lewis and Nico," former F1 race winner and rally driver Robert Kubica, who raced the pair in 2000, told BBC Sport. "They would even have races to eat pizza, always eating two at a time.
"There was always competition. They always wanted to win, to beat each other. 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."
Rosberg and Hamilton's friendship goes back more than 14 years, when they would hang out all day and all night at kart races across the world.
They even shared a hotel room, which according to Rosberg was the scene of many wrestling matches between them. "It was so competitive between us," said the German at the recent Brazilian Grand Prix. "It's the same today."
Dino Chiesa, their old karting boss, added in an interview with BBC Sport: "Many times I was called by reception about some problem in the room. It might be noise or they might have broken something. They would never sleep, so they were always tired the next morning.
"Both liked ice cream so much, particularly vanilla. During the night, they wanted to eat ice cream always, so I had to go out everywhere and find some to keep them happy. They were just kids."
There's a break between races. But the competition doesn't stop. There's table tennis, football in the park, video games at the track and even riding a unicycle.
"Probably the first bit of real competition we had was when Nico used to ride a unicycle everywhere," said Hamilton. "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."
Rosberg has said it took Hamilton only two hours to teach himself how to do it.
Hamilton added: "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.
"We were just arriving and enjoying go-karts and eating pizzas every weekend, fighting all the time and just having fun, whereas now it's all business."
Rosberg added: "It is amusing because there are a lot of similarities [between this year and 2000]. Every other day there are moments or things that pop up and I can smirk and think, 'that's exactly the same as it was 15 years ago'."
That relationship has been tested this season, with the pair going wheel-to-wheel in Bahrain, while Hamilton was furious with Rosberg after an incident during qualifying for the Monaco Grand Prix.
"Nico and I can count our friends on one hand," he said at the time. "Nico does not come into those five friends I have, and I don't come in the five friends he has."
That came after Rosberg, following an early season defeat by Hamilton, said: "[Lewis will] break me down mentally? Well, good luck with that one."
Their rivalry has also been likened to that of Ayrton Senna and Alain Prost. Hamilton takes on the role of Senna, the intuitively talented racer who went all out for victory, while Rosberg shares similarities with 'Professor' Prost - a man whose consistency and calculation of a situation brought reward.
Was that always the case?
"Nico is calm and polite," said karting boss Chiesa. "He is less childlike because he is the single child in the family. Lewis is a bit more strong. He wants to play more, fight more, joke more."
It's a typical karting race day and baking hot. There are a few hours to kill in between races. According to Kubica, Rosberg - who grew up in Monaco - would head to the motorhome of his father, 1982 world champion Keke, to have a rest and cool off.
Hamilton, son of a British Rail worker and council-house tenant, didn't have that luxury. On karting trips, he would have his box trailer and a pot of noodle soup.
But despite the gulf, the pair would still hang out together. Did they ever talk about one day reaching Formula 1? "We were talking about how cool it would be, one day, if we were in Formula 1, just how cool it would be to be team-mates. We said it several times," said Hamilton.
"I can't remember back then if I believed it. Nico would say 'when I'm in Formula 1', and for me it was 'if I ever get to Formula 1'. Because obviously Nico's dad was a Formula 1 driver - he knew he was going to make it.
"For us, we never really knew what was going to happen, we just kept at it."
It's March 2008 and the season-opening grand prix in Australia. Hamilton has a storming race, clinching victory for McLaren. Almost as impressive is Rosberg's drive to third in a midfield Williams.
Hamilton and Rosberg embrace on the podium. This was a big moment in their lives. It was the first time they were on the podium together as F1 drivers.
"Half an hour after the podium, Lewis called me to say, 'hey, did you watch the race? We are on the podium in Formula 1 together finally'," recalled Chiesa.
"That was something special for me, to have a call from Lewis after that one. Nico called me, too, but I speak to him on a more regular basis."
This season, they're doing more than just sharing a podium by coincidence - they're fighting for the title. How did they cope when they were rivals in 2000?
"Sometimes they would argue," said Chiesa. "At that time, I think Lewis had more talent than Nico. At the end of the race, it was usually Lewis who was the winner. If he was not the winner, he was in front of Nico.
"You could see that it was easier for Lewis to reach the limit, he can brake late, he can take more speed into the corners, he can make better manoeuvres to overtake. He just has more talent. Nico was clever to understand the situation quickly and to learn from Lewis."
It's September and Hamilton has just won the Italian Grand Prix, with Rosberg second. Hamilton is understandably delighted, especially after the Spa episode, while Rosberg is happy to take the positives from finishing second.
Was it the same when they were kids? "Nico accepted finishing second in a race but Lewis always wanted to win," said Chiesa. "He didn't like to finish second. He was always fighting to win.
"Because Lewis knew he was the best, he wanted to be the best. For him to finish second in a race is really bad, he would be really upset. He would cry. That has happened many times, when he doesn't win."
At the final race in Abu Dhabi, though, the only tears that may have fallen from Hamilton's face will have been ones of joy.