Defending World Champion Alain Prost journeyed to the penultimate round of the 1986 championship in Mexico City knowing that it could be his last chance of retaining the title. By contrast, Britain's Nigel Mansell had dominated the previous round in Portugal and enjoyed a ten-point advantage over team-mate Nelson Piquet with the Frenchman a further point behind. With Ayrton Senna (Lotus) virtually out of championship contention, it was therefore down to the McLaren team to mount the only real challenge to the Williams Hondas. The video cameras capture all the drama of the closing stage of the best championship for years.