Defending champion Cleveland and powerhouse Golden State enter Sunday's start of the playoff semi-finals pushing toward an unprecedented third consecutive NBA Finals showdown, adding more sparks to an already historic rivalry. Golden State entertains San Antonio in Sunday's best-of-seven Western Conference final opener while the LeBron James-led Cavaliers await Monday's game-seven winner between Boston and Washington in an Eastern Conference final that begins Wednesday in Cleveland. No two teams have ever met for the title in three consecutive seasons, as the Cavs and Warriors could, and only a handful of players have made the NBA Finals seven years in a row, as James could do.