Sebastian Vettel and Fernando Alonso go into the final race of the Formula One season in Sao Paulo on Sunday separated by 13 points.
It is the 27th time in the history of F1 the championship battle has gone down to the wire, with a third world title on the line for both men.
Here, we look at the various scenarios as to how each driver could win the title.
FOR VETTEL TO WIN THE CHAMPIONSHIP
If Vettel finishes in the top four, it does not matter where Alonso finishes, he will be champion.
If Vettel is fifth, sixth or seventh he can only be denied if Alonso wins.
If Vettel is eighth or ninth, he can only be denied if Alonso is first or second.
If Vettel is 10th or is outside the points, he can only be denied if Alonso finishes in the top three.
FOR ALONSO TO WIN THE CHAMPIONSHIP
If Alonso wins he has to hope Vettel finishes no higher than fifth.
If Alonso is second he has to hope Vettel finishes no higher than eighth.