Petra Kvitova claimed a straight-sets win over Caroline Garcia to send the Czech Republic into their fourth Fed Cup final in five years.
The defending champions led 2-0 after the first two singles rubbers on Saturday and the world number four duly finished off the tie with a 6-4 6-4 success on Sunday.
Kvitova - making her return from a two-month break for exhaustion - said: "I knew what I should expect. I saw Garcia yesterday when she played against Lucie [Safarova] and she played very well.
"I was prepared for a very tough match and I was lucky to break her at the beginning of the [first] set. I was a little bit more relaxed than I was before. I'm glad that my serve worked much better than yesterday.
"Two wins during the weekend is always great and I am glad to have them for sure."
The Czech team will face Russia in the showpiece after they saw off a valiant comeback attempt from Germany in the other semi-final in Sochi.
Having fallen 2-0 behind on the first day, Germany battled back with dominant singles victories from Andrea Petkovic and Angelique Kerber over Svetlana Kuznetsova and Anastasia Pavlyuchenkova.
But Pavlyuchenkova recovered to ensure Russia's progress and prevent a repeat of last year's final with a 6-2 6-3 triumph alongside Elena Vesnina in the doubles rubber versus Petkovic and Sabine Lisicki.
In the play-offs, Serena Williams' 4-6 7-6 (7-3) 6-3 over Sara Errani was in vain as United States missed out on promotion to World Group I after defeat by Italy.
Christina McHale was beaten 6-1 6-1 by Flavia Pennetta, who then teamed up with Errani to complete a dramatic victory by overcoming Williams and Riske 6-0 6-3 in the doubles encounter.
Elsewhere, the Netherlands completed a 3-1 win over Australia to win promotion to World Group I, as did Switzerland against Poland thanks to a superb performance from Timea Bacsinszky.
Bacsinszky completed a singles double over the Radwanska sisters by hammering Agnieszka Radwanska 6-1 6-1, only for Urszula to send the tie to a decisive doubles clash with a 4-6 7-5 6-1 win over returning legend Martina Hingis.
But Bacsinszky capped a fine display by mounting a comeback with Viktorija Golubic in the doubles, the Swiss pair recovering from a set down to come through 2-6 6-4 9-7.
Romania progressed at the expense of Canada after triumphing 3-1.
