The 2005 season began on April 23, 2005, on the weekend of the San Marino Grand Prix at the Autodromo Enzo e Dino Ferrari in Imola, Italy. In the pre-season test to decide the inaugural season's car numbers, the iSport International and HiTech/Piquet Racing teams showed a competitive edge. The latter team was largely funded by the former Formula One world champion Nelson Piquet in order to aid his son's route to the premier Formula sport. The championship lasted 23 rounds, two races occurring a weekend with the exception of a single race in Monaco. It was won by German Nico Rosberg, who was subsequently hired by the WilliamsF1 Team, with Heikki Kovalainen finishing second. It was also notable for being the only season that GP2 used grooved tyres like F1 cars rather than slicks. 2006 The 2006 season was the second of the series. After championship holder Nico Rosberg's move to the Williams F1 team, and runner-up Heikki Kovalainen's move to be reserve driver at Renault F1, Nelson Piquet Jr. in the Piquet Sports car was installed as the early title favourite, though the ART Grand Prix cars of Alexandre Prémat and Lewis Hamilton also had fairly short odds, given ART were reigning champions. For the first time, the season began on a calendar separate to the 2006 Formula One calendar, starting out at the Circuit de Valencia, in Valencia, Spain on April 8, 2006, with Piquet Jr. the first victor. Piquet raced into an early lead before Lewis Hamilton came back into the fray. A dominant run by the Briton took him into the championship lead before the balance came back into Piquet Jr.'s favour. After an exciting championship battle lasting 20 races, Hamilton claimed the title in the penultimate race, at the Autodromo Nazionale Monza, in Monza, Italy, and celebrated with a second place in the 21st and final round. 2007 The 2007 GP2 Series began on 13 April at the Bahrain International Circuit, and completed on 30 September at the Circuit de Valencia (which was the only race that wasn't on the F1 calendar). Eventual champion Timo Glock was a driving force throughout the series but came under stiff competition from Lucas di Grassi in the closing stages- however, with a convincing win at the last race in Valencia, Glock sealed the championship. The season was the last with the first-generation chassis, the GP2/05. 2008 The