The victory was a confidence boost for the hosts, who had won just one of their last seven matches and whose qualifying campaign for the 2014 World Cup is going badly with three defeats in four games.
Bale put Wales ahead in the 21st minute when he got an exquisite first touch on a long ball from Joe Allen before taking it on to his devastating left foot and sending it into the far corner.
So often the one shining light in an otherwise ordinary Welsh side, Bale was instrumental in the second goal when his inch-perfect cross from the right found the head of Sam Vokes who nodded home seven minutes after the break.
Bale missed the chance to put the game out of reach when he shot narrowly wide and he left the pitch to a standing ovation when he was substituted on the hour mark.
Austria pulled one back through Marc Janko's 75th-minute header from Marko Arnautovic's cross as the visitors finally made something of a series of testing balls into the box.
That goal prompted Austria to increase the tempo and Wales were left desperately holding on as the dangerous Arnautovic had a free-kick deflected over the bar and the visitors kept pushing for an equaliser that never came.
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