The pair battled Alexander Peva and Oliver Marach in an epic 7-6 (7-1), 6-7 (7-9), 7-5, 3-6, 6-4 win to cut Austria's lead in the best-of-five series to 2-1.
Austria can still clinch the first-round series on Sunday when Jurgen Melzer faces Alex Bogomolov in reverse singles play. Andreas Haider-Maurer faces Russia's Igor Kunitsyn in the fifth rubber match.
The winner will advance to the quarterfinals in April and face defending champion Spain.
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