Petrik competed at the 1966 World Championships where she shared in the team silver medal (gold went to the Czechoslovaks) and earned an individual bronze medal on the beam. She also competed at the 1968 Summer Olympics in Mexico City, where she received a gold medal in floor exercise (shared with Věra Čáslavská), a gold medal in team combined exercises, and a bronze medal in balance beam.[1][2] Her gold medal on floor was very controversial because originally, Čáslavská won outright. After the competition was concluded, Petrik's prelims scores were changed to let her tie with Čáslavská, an action which caused Čáslavská to publicly defy the Soviets who had recently invaded her home country.