Late additions Tomas Berdych and Radek Stepanek won the doubles match to give the Czech Republic a 2-1 lead in their Davis Cup semifinal against Argentina.
They defeated Eduardo Schwank and Carlos Berlocq 6-3, 6-4, 6-3.
Czech captain Jaroslav Navratil replaced his announced doubles pair of Lukas Rosol and Ivo Minar with Berdych and Stepanek, using his top two players in a risky move to get an edge going into Sunday's decisive reverse singles.
Berdych will face Juan Martin del Potro in the first match and Stepanek will play Juan Monaco.
Argentina is trying to reach its fifth Davis final. It has lost a record four finals, including last year against Spain. The Czechs won as Czechoslovakia in 1980.