In 2005, Piquet took part in the A1 Grand Prix for A1 Team Brazil. He won both the Sprint and Main races at the 2005-06 A1 Grand Prix of Nations, Great Britain, the first ever A1 race. He also set the fastest lap. He drove in the GP2 Series, winning his first race at Spa Francorchamps in Belgium, and tested for the BAR-Honda Formula 1 team.