Coulthard left for Red Bull Racing in to be replaced by former CART champion Juan Pablo Montoya for what was McLaren's most successful season in several years as he and Räikkönen won ten races. However, both the team not being able to work out why the car could not heat its tyres properly in the early stages of the season and the overall unreliability of the MP4-20 cost a number of race victories when Räikkönen had been leading or in contention to win and also costing him grid positions in some qualifying sessions, which allowed Renault and their driver Fernando Alonso to capitalise and win both titles.