Hosts Czech Republic are one match away from winning the Davis Cup after edging into a 2-1 lead against holders Spain.
Tomas Berdych and Radek Stepanek were the heroes on Saturday as they delighted the 14,000-strong crowd with doubles victory over Marcel Granollers and Marc Lopez.
The Czech pair dropped the first set but reeled off the next three to win 3-6, 7-5, 7-5, 6-3 in three hours and 19 minutes.
"That's all we wanted," said Berdych after the game. "We are still missing a lot, it's just one point (match), but we are looking ahead and we will do everything on Sunday."
Lopez and Granollers are sixth and 10th in the ATP doubles rankings, while Berdych is down in 119th, but the Spaniards couldn't repeat the form which saw them take victory in last week's ATP Tour Finals in London.
Saturday's result means victory for either Berdych or Stepanek on Sunday will see the Czech Republic lift the trophy.
World number six Berdych takes on fifth-ranked David Ferrer while Stepanek, the world number 37 in singles, will face 11th-ranked Nicolas Almagro after that.
The Czech Republic, which emerged as an independent country after Czechoslovakia split in 1993, has yet to win the Davis Cup although Czechoslovakia triumphed in 1980.
A victory would give the Czechs a rare team double after the women's team defended the Fed Cup two weeks ago.