The definitive March car for the 1972 Formula 1 season was to be the 721X, designed on the basis of the 711 and 721. The basic idea was to redesign the entire weight distribution using a gearbox mounted between the engine and the rear axle. The concept could be valid (it was already used by Porsche and Alfa Romeo) but in March its success was heavily penalized by the behavior of the Goodyear tires, unsuitable for this solution. When it became clear that the 721X could not work, March reverted to the traditional scheme by designing the 721G, built in record time.
Niki Lauda made his F.1 debut at the 1971 Austrian GP with March and agreed to contest the entire 1972 season with the British team. At Jarama, Lauda brought the 721X to the track, with which he also raced the following GP, Montecarlo. On the Monaco street circuit he managed to finish in 16th place despite a pit stop for a wheel change and a fuel leak. After racing again with the 721X at Nivelles, Lauda had the 721G at his disposal.