(Recasts after River Plate win, fan violence) * Rival fans fight on highway close to stadium * River's 2-1 victory puts them top of championship March 10 (Reuters) - River Plate fans clashed with Colon supporters in a running battle on a Buenos Aires highway and local media reported a fan had been stabbed in further fighting near River's Monumental stadium before the home side's 2-1 win on Sunday.