Nico Rosberg under a cloud as rain threatens to shake-up F1 Brazilian GP

• Lewis Hamilton dominates both Friday practice sessions
• Win in Brazil would give Mercedes driver Rosberg his first F1 title.

Nico Rosberg may pretend he does not think about winning the Formula One world championship but the thought probably occurred to the Mercedes driver at least half a dozen times as he strolled through the paddock at Interlagos on Friday.

He has won here for the past two seasons and victory on Sunday, which would be his 10th of the season, would be enough to win the title he so covets.

Related: Damon Hill: ‘I thought butter wouldn’t melt in Nico Rosberg’s mouth’

Another thought may have entered his mind: it could rain and the forecast for a rather mixed day suggests it will at some point in the afternoon. Things happen at this bumpy, relatively short track, with its demanding corners and testing elevation changes – and that is when it is dry. When it rains in São Paulo, all bets are off.

In extraordinary times Rosberg would be a rather ordinary champion, which is not to denigrate his all-round excellence. You search in vain for the specialness, the stardust that marks greatness, and there is certainly nothing special about his ability to drive in the wet, where his team-mate Lewis Hamilton is supreme.

When it rained in Monaco, a very subdued Rosberg was seventh, while Hamilton carried the day.

Rosberg leads by 19 points, so a second and third place in the final skirmishes, here and in Abu Dhabi, would suffice. Hamilton must look to win and hope something unfortunate befalls the diligent German.

Four years ago it rained and chaos ensued. Sebastian Vettel was twice hit by Bruno Senna and lost radio contact. “I think everything that could go wrong, went wrong,” Vettel said. He managed to nurse his damaged Red Bull to sixth place in a rollercoaster race to win the title for the third time.

That 2012 Brazilian Grand Prix represented Jenson Button’s and McLaren’s last victory. The 36-year-old, who will almost certainly drive his last F1 race in Abu Dhabi on 27 November, knows all about the conditions.

“If it’s wet here, I back Lewis for the title, if it’s dry, Nico. I think the idea of a wet race will worry Nico and then the pressure is there, definitely. I qualified 14th in 2009 [his championship year]. It was wet and I thought any little movement would be disaster. One little slip is enough to cost you a second, or you put it in the wall.

“Mercedes are that good a bad result for them is second but if it’s wet it definitely mixes it up. I think the Red Bulls will be very strong in the wet. Power doesn’t matter so much then. It could be really exciting.”

There have been 57 Formula One races since the beginning of the 2014 season, when the 2.4-litre V8 engines were replaced by 1.6-litre turbocharged V6s. Mercedes are looking to make it half a century of victories on Sunday and few would bet against that happening.

Hamilton, who has failed to win in Brazil in nine previous attempts but did win his maiden world championship here in 2008 after overhauling Timo Glock on the final lap to secure the fifth-placed finish that he needed to see off the challenge of Felipe Massa, drew first blood on Friday by producing the fastest times in both practice sessions held in hot and sunny conditions.

He began by finishing a 10th of a second ahead of Red Bull’s Max Verstappen, with Rosberg 0.230sec off the pace in third. Verstappen’s team-mate, Daniel Ricciardo, was fourth, almost half a second behind Hamilton. Even without rain, Vettel, on fresh tyres, spun off and there were also difficulties for other drivers.

In the second practice session Hamilton produced several outstanding laps. Rosberg was second, 0.030sec behind, followed, surprisingly, by the Williams pair of Valtteri Bottas and Felipe Massa. They were ahead of Red Bull and Ferrari.

It was another dismal outing for McLaren. Button had trouble with his car and then Fernando Alonso was told to jump clear of his at the side of the track because of a problem with the water supply to the energy recovery system.

At least the Spaniard maintained his good humour by playing keepy-uppy with a stone and then by taking over a TV position after the cameraman offered him his seat.

Kevin Magnussen, who finished 16th in second practice, is moving to Haas next season, the 24-year-old Dane deciding not to stay with Renault because he felt the team were not fully behind him.