On 18 September 2007 he drove the Red Bull RB3 at the F1 test session in Jerez. He was third quickest on the day, behind Timo Glock (BMW) and Vitantonio Liuzzi (Scuderia Toro Rosso) but ahead of names such as Rubens Barrichello (Honda) and Nelson Piquet Jr. (Renault). On 16 January 2008 Red Bull Racing confirmed Buemi as their test and reserve driver for the 2008 season. At the 2008 Japanese Grand Prix, Buemi drove the medical car as usual driver Dr Jacques Tropenat had been suffering from an ear problem.