McLaren was Renault's main competitor in the 2005 F1 season. The MP4 / 20, powered by the Mercedes Ilmor V10 engine type FO-110R, had Kimi Raikkonen as its best performer, in the end second behind Alonso with the Renault. During 2005, Juan-Pablo Montoya, Pedro de la Rosa and Alexander Wurz piloted the second car. The MP4 / 20 immediately proved to be competitive, even if at times not fast enough in qualifying. After some problems with the correct functioning of the tires, McLaren had a high level season, finishing second in the constructors' championship behind Renault.