Hosts Czech Republic and holders Spain were tied 1-1 in the Davis Cup final on Friday after Tomas Berdych beat Nicolas Almagro 6-3, 3-6, 6-3, 6-7 (5/7), 6-3 in the second rubber of the day.
Berdych, the world number six and the Czech number one, needed three hours and 58 minutes to see off 11th-ranked Almagro on Prague's hardcourt.
Earlier David Ferrer had put holders Spain ahead after beating Radek Stepanek 6-3, 6-4, 6-4.
Ferrer, the world number five and Spain's number one, outplayed the 37th-ranked Stepanek at the O2 Arena in two hours and 58 minutes.
"I played very well all the match. I'm very happy with my game," Ferrer said just after the rubber.
"We're 1-0 up, but we haven't finished the tie, it's a very long one," he added.
Despite concerns about a very fast court prepared by the hosts, Ferrer said he felt comfortable.
"It was very fast but I received very well and this maybe was the key," he added.
Before the rubber, Ferrer predicted a close game recalling a five-setter they played in the 2009 Davis Cup finals when he finally helped Spain thrash the Czechs 5-0.
But Stepanek, the Czech number two player, offered little resistance.
In the first set, Stepanek came back from 0-40 through 11 deuces in game six but then lost his serve two games later.
Ferrer then took the second set with two breaks against Stepanek's one, before completing the job after converting his second match point following another two breaks in the last set.
Spain are missing world number four Rafael Nadal, sidelined with a knee injury.
They are looking to add a fourth crown to their three Davis Cup trophies from the last four years, after having won the cup in 2000 and 2004.
Czechoslovakia, which split peacefully into the Czech Republic and Slovakia in 1993, won the Davis Cup in 1980.
But if the Czechs win the 100th edition of the Davis Cup finals, they will clinch a rare team double, last achieved by the United States in 1990, after their women's team lifted the Fed Cup here two weeks ago.