In 1990, Petra Krupková won the bronze medal at the Czechoslovak Youth Chess Championship in the U18 girl's age group. In 1992, she shared 4th place in the World Youth Chess Championship in the U16 girl's age group. In 1993, Petra Krupková won the Czech Women's Chess Championship, but a year later she won bronze medal in this tournament. In 1995, in Poland, she shared first place with Monika Bobrowska in the Women's World Chess Championship Zonal tournament and won the right to take part in an Interzonal Tournament. In 1995, Petra Krupková participated in Women's World Chess Championship Interzonal Tournament in Chişinău where ranked 15th place. In 1996, she won the bronze medal in the U20 European Junior Championship in Hungary.