Fernando Alonso drove for Renault when he won the 2005 Formula One World Championship. Racing for the Mild Seven Renault F1 Team, he became the season’s Drivers’ Champion and helped Renault win its first Constructors’ Championship.
Alonso began 2005 strongly, winning three of the first four races in Malaysia, Bahrain and San Marino. Renault’s R25 was fast and reliable, and Alonso’s consistency gave him a major advantage even as McLaren’s Kimi Räikkönen often matched or exceeded Renault’s outright pace.
Alonso clinched the title at the Brazilian Grand Prix with a third-place finish, two races before the season ended. At 24, he became the youngest World Champion at that time. Renault secured the Constructors’ title at the final race in China, where Alonso also won.
The key distinction is between a constructor and an engine supplier. Renault was Alonso’s constructor and team, while other teams, including McLaren, used Mercedes engines. Alonso later drove for McLaren and Ferrari, but neither team was associated with his 2005 championship.