Nobody has won a World Series without losing a postseason game since 1976. Of course, Major League Baseball’s playoffs were smaller back then: The ’76 Cincinnati Reds beat the Philadelphia Phillies in a three-game National League Championship Series, then swept the New York Yankees in a four-game World Series. The playoffs were an even more exclusive affair before that, as the World Series was the only playoff series until MLB added its two championship series in 1969. Twelve teams pulled off World Series sweeps between 1907 and 1966, vanquishing the other playoff team from the opposite leagues.
The currently undefeated Houston Astros, then, would be nearing uncharted waters even if baseball hadn’t expanded its postseason yet again this year. They won 106 games during the regular season and thus got to skip the league’s new wild-card round, starting their playoff run with a three-game divisional series sweep of the Seattle Mariners and an unceremonious four-game dispatching of Aaron Judge and the New York Yankees. A sweep of the Philadelphia Phillies in the World Series would make the Astros 11-0 in the playoffs, a postseason record unlike anything MLB has ever seen — though even winning a five- or six-game series would safely ensconce them among the most dominant teams ever playoffs. Their