After their meeting, world number six and Czech number one Tomas Berdych will take on Spain's Nicolas Almagro, the world number 11.
In Saturday's doubles, Czechs Lukas Rosol and Ivo Minar are due to face ATP Tour Finals winners Marcel Granollers and Marc Lopez - but the Czech team is likely to make a change and rely on Berdych and Stepanek instead.
On Sunday, Berdych will face Ferrer before Stepanek takes on Almagro.
The 100th edition of the Davis Cup final will be played in front of almost 14,000 people -- a crowd that pushed the Czech women's team to a successful Fed Cup defence following a final victory over Serbia two weeks ago.
A Davis Cup win would give Czechs a rare team double -- last achieved by the United States in 1990.
Spain are looking to add another crown to their three Davis Cup trophies from the last four years. They also won the competition in 2000 and 2004.
In 2009, Spain thrashed the Czech Republic 5-0 in the Davis Cup final in Barcelona.
Czechoslovakia, which split peacefully into the Czech Republic and Slovakia in 1993, won the Davis Cup in 1980 with a team led by the then 20-year-old Ivan Lendl.