Who will win the championship showdown?
Ultimately Fernando Alonso is going to need something to go wrong for Sebastian Vettel to win the title, but anything can happen in a final race decider.
On a normal weekend where everything goes according to plan Vettel ought to finish in the top four (which would guarantee him the title), with no issues whatsoever.
However as history shows title deciding races are far from normal. So much can go wrong, as the pressure on the drivers and teams is even higher than usual. Nerves and tension play a huge part. All this can lead to mistakes, which wouldn’t be made in normal circumstances.
As double world champion Mika Hakkinen says: "Deciding the championship in the last Grand Prix is nerve wracking. I do not recommend it to anyone."
The fact that some of the most dramatic F1 races of all time have been title deciders is not just a coincidence.
Furthermore Interlagos has a rich history for producing races which don't follow the script. It's probably one of the most difficult places to go and decide a championship.
On paper at least, Alonso faces an uphill struggle to beat Vettel to the title. He is 13 points behind him in a slower car. If anything, Ferrari fell even further behind Red Bull in Austin.
Even worse still is that McLaren and Lotus are also looking extremely quick at the moment. They could have a huge say in who wins the title, especially Lewis Hamilton who has found some great form lately.
The layout of the circuit should be better for Ferrari, whilst not being quite as strong for Red Bull. Ferrari ought to fare very well in sectors one and three where straight line speed is crucial, which of course is Red Bull’s achilles heel. However Red Bull will be on top in the curves and twists of sector two.
Historically Interlagos has been a very strong track for Ferrari, where they have enjoyed dominant victories in the past. However track configuration alone is not going to be enough to bridge the gap they have to Red Bull at the moment.
As well as delivering another great performance Alonso will be relying on the unpredictability of a final race decider, and the Interlagos circuit. Recent history shows that, the long odds contender going into the season finale can come out on top.
In 2010 Vettel was 15 points behind championship leader Alonso going into the final race at Abu Dhabi. A disastrous strategy call from Ferrari handed the title to Sebastian.
In 2007 Kimi Raikkonen was seven points (the equivalent to 17.5 points under the current system) behind Hamilton going into the season finale in Brazil. Lewis made a mistake on lap one whilst trying to overtake Alonso, and then a temporary gearbox glitch helped Raikkonen to a shock championship win.
Going further back to the showdown at Adelaide in 1986 and Nigel Mansell led Alain Prost by six points, and Nelson Piquet by seven points. A podium would have ensured Nigel won the title.
It was all looking good until that memorable tyre explosion, and Mansell’s title dreams were instantly shattered. Prost went on to win the title.
Ferrari's poor strategy left Alonso stuck behind Petrov during the 2010 title decider (© Renault/Lotus/LAT).
These three examples show how easy it is for something to go wrong for the favourite in the title decider.
Reliability is going to be a huge worry for Vettel and Red Bull. In Austin Mark Webber retired because of another alternator failure. This is the fourth time this season that an alternator failure has resulted in a DNF for one of the Red Bull drivers.
In Brazil, Red Bull will be switching to the new alternator. They will be keeping their fingers and toes crossed that it is reliable this weekend.
Adrian Newey says: "Our third alternator failure of the year is a bit of a ticking time bomb. You never know when that one is going to strike."
However the alternator isn’t the only reliability concern for Red Bull. Recently there have been water leakages on both cars. We have also seen issues with KERs on Webber's car. There will be the fear that the same could happen to Vettel.
This year Ferrari has been near bullet proof. An issue in qualifying in Monza has been the only occasion poor reliability has struck. Whilst that will be reassuring to Fernando, there is always that nagging feeling that something could go wrong at the worse possible moment.
Undoubtedly the weather could play a pivotal role with rain predicted throughout the weekend.
Rain in the 2008 title decider transformed it into one of the most dramatic showdowns of all time. A late shower gave McLaren an incredible tactical dilemma. It was 50/50 whether the right call was to switch to wets or try and survive till the end on dries. In the end wets was the right decision, but only by a whisker.
The appearance of rain simply increases the amount of things that can go wrong. One of the title contenders could aquaplane in a puddle, make a bad call on the tyres or have an incident with another car. Plus in the rain there is always that lottery element too.
Overall you would say rain would favour Fernando. The Ferrari has been very strong in the wet this year. It would allow Alonso to compete on a level playing field with Vettel.
It would also potentially bring drivers from further down the grid into the mix too, as we saw with Sergio Perez in Sepang.
The variables and hazards that a wet race brings would give Fernando a better chance of outscoring Seb by 14 points.
There is also the question of which driver will suffer most from nerves? Generally it’s always much easier to be the chaser in the championship final.
All the pressure is on the points leader to get the job finished. This will apply even more in Sebastian’s case as not only is he the points leader, but he also has comfortably the best car out of the two contenders.
Alonso is in a no lose situation. Nobody realistically expects him to win the title on Sunday, but if he does he will be lauded as the driver who managed to achieve the near impossible.
You also have to consider how badly Sebastian wants to win a third championship. It’s not every day you get the chance to win three championships back to back. He may never find himself in this position again
For a man obsessed with F1 statistics he will certainly be fully aware of what he is so close to achieving. You could liken it to being just a few steps away from conquering Mount Everest. Imagine the agony if you got that close but didn’t make it to the top.
Vettel hasn't been immune to problems this season (© Red Bull/Getty Images).
We have also seen some a few jitters from him recently. We heard how agitated he was on the radio after hitting the DRS board in Abu Dhabi, and then again after Hamilton overtook him for the lead in Austin.
You can be sure that Alonso will be his usual calm self. The man is made out of steel. Nothing will bother him.
Out of the pair you sense that Vettel is the more likely one to suffer from a few nerves during the race weekend.
Vettel’s best chance of succeeding this weekend is to just keep his approach the same. Nail pole position and scamper away in the race. That will be the best way of keeping out of trouble.
If he doesn’t end up leading after turn one he will have a much tougher task, particularly with Red Bull’s lack of straight line speed making him vulnerable.
Christian Horner says: "We just have to approach the next race as we have the previous 19."
He added: "We have to go there, attack the weekend, and get the best out of ourselves; the car, the strategy, the drivers, and reliability.
Alonso just has to do what he has been doing all season long and just pull another rabbit out of the hat. It’s been the party trick that has kept him in with a chance of winning the title.
The role of the team mates of both contenders will be another intriguing factor. Massa has been on his best form for a long time, and his home race has often inspired him to a great result.
However Sao Paulo is also a very strong track for Webber. He has two wins and a second place in his last three visits to the track. However you sense Mark would rather his friend Alonso won the title. Just how hard will he be trying to help Seb win the title?
The wise money this weekend will be on Vettel to win his third title. However the way 2012 has gone, plus the fact the title will be decided at Interlagos, you just wonder if there is one last twist in this incredible season.