When advancing to higher leagues, you unlock new tracks to race on in Duels. By default, the tracks of Great Britain and Spain are already available for you to race on, since these are the only tracks available in League 8 (the league all players begin in).
If you are promoted for the very first time to League 7, you will unlock the tracks of Brazil and Austria in Duel mode.
If you are promoted for the very first time to League 7, you will unlock the tracks of Brazil and Austria in Duel mode.