Klemenschits formed with her twin sister Sandra to 2006, the strongest women's doubles Austria. 2005 denied the two sisters two games in the Fed Cup. On ITF level won Daniela Klemenschits, almost always in a team with her sister, between 2000 and 2006 22 Double Tournaments. In August 2005 she was in a double 95 in the world rankings, their highest position in the individual was the 356th place in July 2001.
Both sisters sick in early 2007 to a squamous cell carcinoma, a cancer of the abdomen. Their fate sparked a worldwide media coverage of, as at the initiative of Barbara Schett and other a fundraiser on the WTA Tour and the ATP World Tour came about, with the proceeds of the costly treatments were funded. While Sandra was cured, Daniela died in April 2008. Their disease was too far advanced.