In a World Cup race Mitterstieler drove for the first time on February 4, 1996 in Latsch , in the fifth race of the 1995/1996 season , as third on the podium. After further podium places initially failed to materialize, and she had not started at World and European Championships in 1997 and 1998, she celebrated her first World Cup victory two years later, on February 8, 1998, in Železniki , Slovenia . A week earlier, she had not qualified for participation in the World Cup within the strong Italian team. She finished the 1997/1998 World Cup season with a second place at the finals in Mölten . In the following 1998/1999 season , Mitterstieler celebrated her second World Cup victory on January 24, 1999 in Canale d'Agordo . In the other races of the season, she achieved placings between fifth and eighth, placing her in the top six for the first time in fifth in the overall World Cup. At the European Championships in 1999 in Szczyrk , she finished fourth, but missed the medal ranks relatively significantly with a gap of around 1.7 seconds on third-placed Christa Gietl .
In the next few years there were no top results in the World Cup and several times she was unable to qualify within the Italian team for one of the four World Cup starting positions that each national association is entitled to per race. She was also not at the start at world and European championships from 2000 to 2002. Things went up again in the 2002/2003 season , in which she first regularly drove back to the top five in World Cup races and finally won the bronze medal behind Sonja Steinacher and Jekaterina Lavrentjewa at the 2003 World Championships in Železniki on February 8th . A week after the World Cup, at the end of the season, she also achieved her first podium finish in four years in the World Cup by finishing third in the final in Olang , making her fifth in the overall World Cup for the second time. The next winter , however, Mitterstieler only competed in two of the six World Cup races, which she finished in fourth and fifth. At the 2004 European Championships in Hüttau , she only finished 13th.
The 2004/2005 season was successful . In the first World Cup race of the winter Mitterstieler did not qualify for a starting place, but in the other five races of the season she made it onto the podium three times. She finished second in Unterammergau and third in Oberperfuss and Latzfons, and thus achieved third place in the overall World Cup behind Renate Gietl and Jekaterina Lawrentjewa. At the 2005 World Championships in Latsch Mitterstieler was still in the lead after the first race, but only drove the eighth and sixth fastest times in the second and third races and thus fell back to sixth place in the final standings. In the team competition she was fifth together with Martin Psenner , Günther Innerbichler and Alex Innerbichler . After that winter, she ended her career because of a pregnancy.
Harald Steyrer, Herbert Wurzer, Egon Theiner: 50 years of FIL 1957–2007. The history of the International Luge Federation in three volumes. Volume II, Egoth Verlag, Vienna 2007, ISBN 978-3-902480-46-0 , pp. 285-407.