For so long in the contrails of Lewis Hamilton, a driver with whom he has duelled ever since their days as cherubic karting prodigies, Nico Rosberg knows that he will never have a better chance than this. Here in the sultry heat of Sao Paulo, the German whose driving has become a byword for precision and reliability understands that a victory will be enough to seize his first world title, 34 years after his father Keke did the same.

The only problem is that it is forecast to rain. And when the track starts to slicken, there is usually only one winner, and it is not the tanned Teuton with the blond hair. Hamilton, as he proved so often, is without peer in this crop of drivers when it comes to the wet.

Whether in negotiating torrential downpours at the Fuji Speedway in 2007, or carving expertly through late showers to win at Silverstone last year, he has a mastery of damp conditions that should make Rosberg nervous – especially when the sweeping corners of Interlagos look likely to be drenched once more.

Rosberg must just hope there is no repeat of the dramas of 2003, when successive storm-fronts created a scene of aqua-planing mayhem. For while few dispute his technical acumen as a driver, there were doubts expressed privately in the paddock on Friday about his capacity for eyeballs-out racing. Unlike Hamilton or Red Bull’s Daniel Ricciardo, Rosberg is not a natural wheel-to-wheel aggressor. So consistent is he with his starts that his overtaking manoeuvres this season could be counted on one hand.

The margins are wafer-thin, but Rosberg’s perceived lack of belligerence could be the one factor that denies him recognition among Formula One’s truly exceptional talents.

Niki Lauda, Mercedes’ non-executive chairman, has intimated as much, once arguing that Hamilton at his fastest has as much as a two-tenths of a second advantage per lap over his Mercedes team-mate. In the final analysis, though, on Sunday's title decider in Brazil rests firmly in Rosberg’s hands. Win, and he would secure the title that his charismatic father once inspired him to pursue. Spin out, as he might be prone to do on a wet and wild afternoon, and the slugfest would roll on to Abu Dhabi in a fortnight’s time.

Rosberg could, remarkably, seal a 10th world championship for Germany in just 17 years, after the supremacy of Michael Schumacher and Sebastian Vettel. Not that he is celebrated to anything like the same extent in the country he calls his own. The problem, as Hamilton put it less than tactfully at Hockenheim in 2014, is that Rosberg is “not really German”.

According to his arch-rival, he would never even stand in front of the German flag during their junior years. He is half-Finnish through Keke’s ancestry and spent much of his childhood in Monte Carlo. Every inch a citizen of Europe, he is smooth, cosmopolitan and a brilliant linguist but not, alas, a character who inspires intensely partisan passions.

Bernie Ecclestone has noticed as much, effectively telling Rosberg to his face that he lacked charisma. In one toe-curling moment on the grid in Monaco last summer, he said to him: “I am a huge Lewis fan, because he is a super promoter of the sport. From a pure business aspect – sorry Nico, I have to say this – you are not so good.”

Hamilton hardly has to worry, then, about where he stands in relation to Rosberg in the popularity stakes, but it is this title battle that consumes his every waking hour. A combination of poor starts and rotten luck have sabotaged his campaign, and yet he can be comforted that the momentum is in his favour. Brilliantly composed for his two recent wins in Austin and Mexico City, he arrives in Sao Paulo, the setting for his extraordinary last-gasp title triumph over Felipe Massa in 2008, with his confidence heightened and his resolve strengthened.

It is a mystifying omission on Hamilton’s CV that he has never won in Brazil, but he argued that he felt pressure from history. “I have had lots of great and mixed experiences here, so it is a real challenge to come here and try to win for the first time,” he said. “That’s my goal. I have nothing to lose.”

Rosberg, by contrast, has everything to lose, and it is for this reason that he refuses even to contemplate his potential celebrations on Sunday. “I have not wasted one single thought on that,” he said, sternly. “On a weekend like this it is important that you stay in your comfort zone, that I have time to be on my own. That is an important aspect, that I am not drawn into a negative spin from any outside incidents.”

So far, the portents are promising for Hamilton. He finished at the top of the time-sheets in both practice sessions on Friday, even if Rosberg ran him close. As ever, the two Silver Arrows cars were streaking over a distant horizon from their nearest pursuers. It is necessary to remember sometimes that the closeness of the contest between the drivers has rescued the season, such is Mercedes’ crushing dominance.

Since the dawn of the V6 engines, introduced at the start of 2014, this all-conquering team have lost a mere eight races in three seasons. It can scarcely be in the sport’s long-term interests for this one-sidedness to be sustained. Formula One, after all, needs injections of energy and entertainment wherever it can find them. Rosberg, should he race away to his 10th win in 2016 on Sunday, would be a worthy champion, but whether he is good for business is a moot point.