 Complete the following phrase:  Despite Prost already claiming two Formula One World Championships, the relentless nature of Sennas driving style often challenged the calculated nature of Prosts style. Their contrasting approaches to racing, in combination with both men having a domit car, it was inevitable that there would be highly controversial moments on and off the track. Throughout their time in Formula One Prost finished with 51 wins and 4 world championships. Senna, before his 