The U.S. team opened the tournament with a 3-0 win over Czech Republic, and followed it up with another sweep.
"Jack and I are both here to win and to do well in this tournament, so finals is the first stepping stone and winning each match is a stepping stone to get to the final," Vandeweghe said.
The U.S. secured a place in the final with a match to spare when defending champion Australia lost to the Czech Republic 2-1 later Tuesday.
Nick Kyrgios gave Australia the lead with a 7-5, 6-4 win over Adam Pavlasek, but Lucie Hradecka leveled it for the Czechs with a comeback 4-6, 6-4, 6-4 win over Daria Gavrilova.
Hradecka and Pavlasek combined to win the deciding mixed doubles 3-4 (1), 4-3 (1), 4-2.
Australia lost its opening match to Spain 2-1.