Cut-out-and-keep title reckoner.

So the Formula One world championship is going to the final round after Lewis Hamilton's unfortunate exit from the Chinese Grand Prix, but who needs to do what now that the points margins have been narrowed.

Hamilton remains favourite to take the title in his rookie year, when he would usurp rival Fernando Alonso as the youngest ever champion, but the Briton would do well to bear in mind the 1986 showdown in Adelaide, when fellow Briton Nigel Mansell went into the final race with a seven-point lead and only nine points on offer for the victory. One blown tyre was enough to make him an outsider, as Alain Prost came through from third favourite status to claim the crown.

And if anyone is thinking that punctures are unlikely at Interlagos, just think back twelve months, when Michael Schumacher saw his slim hope of overhauling Alonso deflated in more ways than one.

This time around, Kimi Raikkonen is the outsider, but the Finn has the most wins this season following his Shanghai success and is perfectly capable of topping the podium again in Brazil. Although a sixth victory would be ideal in his title quest, the Ferrari man would require a large dose of luck and some unlikely Mclaren unreliability.

Or his two rivals to get physical in their own efforts to steal a march on race day....

For those with the nerve to sit through the action on Sunday 21 October, here is a quick rundown of who needs to do what (pending any hitherto unseen protests, appeals and penalties of course...)

Lewis Hamilton will be champion if:

He finishes first or second
He finishes third with Alonso 2nd or lower
He finishes fourth with Alonso 2nd or lower
He finishes fifth with Alonso 2nd or lower (they would be tied on points, but Hamilton would win tie-break based on second places)
He finishes sixth with Alonso 3rd or lower and Raikkonen 2nd or lower
He finishes seventh with Alonso 3rd or lower and Raikkonen 2nd or lower (Alonso and Hamilton would be tied on points, but Hamilton would win tie-break based on second places)
He finishes eighth with Alonso 4th or lower and Raikkonen 3rd or lower (Alonso and Hamilton would be tied on points, but Hamilton would win tie-break based on second places)

Fernando Alonso will be champion if:

He wins and Hamilton finishes 3rd or lower (Alonso would win tie break 5-4 on wins)
He finishes second with Hamilton 6th or lower
He finishes third with Hamilton 8th or lower and Raikkonen 2nd or lower
He finishes fourth with Hamilton not-scoring and Raikkonen 3rd or lower

Anything lower than fourth means Hamilton currently has more points

Kimi Raikkonen will be champion if:

He wins with Hamilton 6th or lower and Alonso 3rd or lower (if Hamilton 6th, Kimi wins 6-4 on wins tie-break)
He finishes second with Hamilton 8th and Alonso 4th or lower (both would result in tie that Kimi wins 5-4 on victories tie-break)

Anything lower than second means Hamilton currently has more points