The Boston Red Sox and St. Louis Cardinals had the best regular season record in their respective leagues at 97-65.

The World Series hasn't had a matchup of regular season champs since the 1999 season. 

The World Series added an extra round in 1969 as previous matchups were determined strictly by regular season records.

The 2004 Cardinals are the only National League team to advance to the World Series with the best regular season record since 1999.