Russian siblings Natalia Soboleva and Andrey Sobolev provided the opposition in the big final but despite the home support the Austrian duo prevailed.
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Ulbing first put Austria in front as she finished 0.33 seconds ahead of Soboleva, with Karl then also went quicker than his opponent.
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In the small final, the Swiss pair of Julie Zogg and Dario Caviezel won bronze by defeating Italy's Nadya Ochner and Aaron March.
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