In the second half of the 1960s, Demetz was by far the most successful ski racer in Italy. From 1965 to 1969 she won ten Italian championship titles in four different disciplines, more than any other athlete during this time. She first appeared internationally at the 1964 Winter Olympics in Innsbruck , two years later she was fifth in the combined and sixth in the giant slalom at the 1966 World Championships in Portillo, Chile .
From 1967 Demetz also took part in the newly created World Cup. She won the downhill in Sestriere on March 3rd of this year , but had to share the victory with the French Marielle Goitschel at the same time . At the end of the season, she was the third best downhill skier in the world. Demetz could not confirm the results of the first World Cup season and she fell into midfield. After missing qualification for the 1970 World Cup, she resigned from top-class sport.