LONDON If Formula One were to produce a good feud guide, the rivalry being cooked up between title-chasing Mercedes team mates Lewis Hamilton and Nico Rosberg would merit several stars.
While their team bosses will do what they can to keep the drivers in check, they will also let them race - which means the increasingly fractious duo will have plenty of fuel in the coming months.
"We are not friends, we are colleagues," Hamilton declared in Monaco on Sunday after Rosberg won the season's glamour race and seized back the championship lead with a four-point advantage.
The 2008 world champion hardly needed to spell that out, the body language doing it for him in a podium "celebration" that ended without handshakes or backslaps between the pair who finished first and second.
"We are living in the same building and I am sure when we turn up in the next place we will be as professional as ever," a calmer Hamilton explained later.
"People say that we are best friends but we are not. We have not been since we were 13 years old. I say hi to him and he says hi to me. We don't have lunch together; we don't have dinners. We are cool."
Rosberg, visiting the German football team on Tuesday, told reporters he was sure relations would improve - even if Hamilton will be hoping the next dish served up in Canada is cold and labelled "revenge".
"We've always been friends, we always will be friends," Rosberg had told Sky TV on Sunday. "But friends is a big word. What exactly is friends? We have a good relationship and work well together."
Much of the spice in the unfolding story is that until this season, in which Mercedes are so dominant that they could end up winning every race, they were as close as any F1 pairing despite being very different characters.
Hamilton and Rosberg, one growing up in social housing and the other among Monaco's millionaires, have known each other since they were teenage team mates in go-karts.
They travelled together and got a glimpse of the good life enjoyed by Rosberg's 1982 world-champion father, Keke. Until recently Hamilton even kept his safe in Rosberg's apartment.
That they should now fall out is par for the course in Formula One.
"You can talk as much as you want about them growing up as friends, but you have to outperform one man," wrote David Coulthard, who sometimes faced a stony silence from double champion Mika Hakkinen during their time together at McLaren, in a Daily Telegraph column on Tuesday.
"No matter how long you have known them, you only find out who they are and what they are really like when the light is shining brightest."
As four-times world champion Alain Prost warned last week, few friendships survive in Formula One when such a prize is at stake and those fighting for it are in the same team.
The Frenchman should know, having partnered the late Brazilian triple champion Ayrton Senna at McLaren in one of the most combustible pairings of all time - and one whose echoes are being detected again.
"Show me a good loser and I'll show you a loser," Hamilton's former boss and mentor Ron Dennis likes to say, and he is certainly not alone in thinking that.
Point out a happy, friendly pair of team mates on the starting grid and it is usually because the pecking order is clearly established - think Michael Schumacher and Felipe Massa during their time at Ferrari - or the car is not good enough to allow either to do much more than take part.
It is no coincidence that Hamilton got on well with Heikki Kovalainen, who posed no threat as a McLaren team mate, but was barely on speaking terms with double world champion Fernando Alonso during their year together in 2007.
Alonso felt Hamilton was favoured by Dennis and seethed. In Monaco, it was Hamilton who felt Rosberg had deliberately stymied him and was similarly aggrieved.
"I wish you could have seen the data," he told reporters on Sunday, referring to the Monaco controversy that saw Rosberg take pole after messing up his final qualifying lap and bringing out warning flags that denied Hamilton a chance to go faster.
"I saw something late on last night, and all I could do was smile."
It may be some time before that smile is directed at Rosberg, however.
But Niki Lauda, the triple champion who is now non-executive chairman of the team and was instrumental in luring Hamilton from McLaren, said he would ask them to show at least a degree of public courtesy, whatever was bubbling away in the background.
"I had the same with Prost. I hated the guy," the Austrian said of the McLaren team mate he beat to the 1984 title by half a point. "But at least I said hello in the morning."
(Editing by Neville Dalton)