 The distinctive needle-nose design was previously used on the MP4-19 in .The MP4-21 was the first McLaren car to be powered by purely Mercedes-Benz engines after 11 years partnership with Ilmor as an engine builder.The car started the season in the hands of Kimi Räikkönen and Juan Pablo Montoya, but after a few races it soon became clear that it was not as competitive as its predecessor, the MP4-20, with an apparent improvement in reliability countered by an underpowered Mercedes engine.