Hosts Germany snatched a 2-1 victory against holders Sweden with a win in the doubles rubber on Friday to set up a World Team Cup final against Serbia.
Nicolas Kiefer and Mischa Zverev carved out a thrilling 7-6, 4-6, 13-11 win against Robin Soderling and Robert Lindstedt to give the Germans the winning point and reach the final in Duesseldorf for the seventh time.
Four-times winners Germany saw the Swedish doubles pair squander two match balls in the third-set tiebreak before Kiefer and Zverev could claim victory after 92 minutes.
"I had the feeling the whole nation was on the court supporting us," said 21-year-old Zverev. "I have never experienced that before. This is the greatest day of my life."
The Germans, trailing 1-0 after Soderling had crushed Rainer Schuettler 6-0, 6-0 on Thursday, pulled level when Philipp Kohlschreiber beat Andreas Vinciguerra 6-1, 6-2.
Kohlschreiber, who came back from a set down in his previous singles matches, stormed into a 5-0 lead after Vinciguerra missed six break points in the fifth game.The German world number 31 got another two breaks early in the second set.
Serbia, trailing 1-0 going into Friday's matches, made sure of their final spot with world number one doubles player Nenad Zimonjic teaming up with Viktor Troicki to beat Franceso Piccari and Andreas Seppi 6-0, 7-6.
It took the Serbian pair just 15 minutes to grab the first set to love before the Italians staged a fight-back to take the second set to a tiebreak.
Earlier, world number 71 Janko Tipsarevic breezed past Piccari, ranked 406th, 6-2, 6-3 to level the tie 1-1.
Argentina, who needed Serbia to slip up against Italy if they were to reach the final, beat Russia 3-0.
Maximo Gonzalez edged past Evgeny Korolev 6-3, 3-6, 6-3, then teamed up with Juan Martin del Potro to win the doubles after Korolev and Igor Andreev retired at 2-2 in the first set.