After a season-opening road trip -- a long, miserable, soul-searching trip -- the Boston Red Sox already have learned what the 18 previous World Series winners learned: In the current era of baseball, repeating as champion is a formidable task.
Since the Yankees won three World Series in a row from 1998 to 2000, no team has repeated. Only two champions managed to return to the World Series -- the 2000-01 Yankees and the 2008-09 Phillies. (Three other teams have played in back-to-back World Series: the 2010-11 Rangers, 2014-15 Royals and 2017-18 Dodgers.) Nine of the 18 champions failed to make the playoffs the following season.