Boston Red Sox
In 1918, the team won its fifth World Series, and then went into one of the longest championship droughts in baseball history. The Red Sox won the World Series in 1903, 1912, 1915, 1916, 1918, 2004, 2007, 2013, and 2018; they won the pennant, but lost the World Series in 1946, 1967, 1975, and 1986.