Washington needs two wins in five National League Championship Series games to secure its first-ever World Series appearance.
The Nationals play the next three contests on home soil, where they have two victories against a pair of foes this postseason.
St. Louis performed well on the road in the NLDS versus Atlanta, but it needs a much better effort at the plate to win a single game.
At the moment, Washington is a significant favorite to advance to the Fall Classic at -600 (bet $600 to win $100), while the Cardinals are underdogs at +450 (bet $100 to win $450), per Caesars.