Nemetz won her first major medal at the 1980 World Championships in Athletics. This was a two-event competition created by the International Amateur Athletics Federation in response to the lack of the women's 400 metres hurdles and 3000 m run at the 1980 Summer Olympics. Nemetz took the 3000 m silver medal behind Birgit Friedmann. Her runner-up time of 8:50.22 minutes was a new Swedish record and she was the first to beat Inger Knutsson's Swedish time for that distance. Nemetz's time stood for almost sixteen years, at which point Sara Wedlund improved the mark by a second and a half. Nemetz also retained her Swedish short cross country title, but Katharina Jönnå and Birgit Bringslid took that year's Swedish track titles. She won the 3000 m at the 1980 DN Galan in Stockholm.