India's first Formula One driver Narain Karthikeyan on Friday made a full-time switch to sports car racing, ending his around two-decade-old single-seater racing career. Karthikeyan, who has secured a spot in Japan's Super GT series, will be competing with the likes of former Formula 1 world champion Jenson Button. The 41-year-old last raced in Formula 1 back in 2012.