After battling to singles wins on Friday, Radek Stepanek and Lukas Rosol paired up for a 6-4 6-4 6-4 victory over Tatsuma Ito and Yasutaka Uchiyama at the Ariake Coliseum to set up a last four encounter against either Germany or France.
In a match that lasted two hours and 20 minutes, the Czech pairing won all three sets with a break of serve in the 10th game against the error-prone Japanese to remain on course for a third straight Davis Cup title and fourth overall.
Rosol was brought in as a substitute for Jiri Vesely by Czech captain Jaroslav Navratil on Saturday morning and the move proved inspired with the world number 40 exhibiting a strong serve and playing especially well from the baseline.
On Friday, former world number eight Stepanek, now 47th, came from a set down to beat Ito 6-7(5) 7-6(5) 6-1 7-5 before Rosol survived a mid-match meltdown to overcome 21-year-old Taro Daniel 6-4 6-4 3-6 4-6 6-2 in the second rubber.
Both sides came into the contest without their top players.
World number five Tomas Berdych is out for the Czechs following two tough tournaments in the United States, while Kei Nishikori is sidelined with a groin problem suffered in a victory over Roger Federer at last week's Sony Open in Miami.
The Czechs are likely to face Germany in September's semi-final encounter after Carsten Arriens' unfancied side opened a 2-0 lead over the French on the opening day of their tie in Nancy.
- Sports & Recreation
- Lukas Rosol
- Radek Stepanek
- Tatsuma Ito