A year later, she qualified to the 2000 Sydney Olympics going to the 400 meters finals, finishing with a reasonable 5th place with a time of 49.96 seconds.

Unfortunately, she could not keep the fast pace and was passed by Amy Mbacké Thiam from Senegal and Lorraine Fenton from Jamaica with no more than 20 meters to go.

In 2002, she won all seven competitions of 400 m of the Golden League (Oslo, Paris, Rome, Monaco, Zürich, Brussels and Berlin) sharing the jackpot of one million dollars in gold bars with three athletes.

A year later, at the 2005 World Championships in Athletics, she won the bronze medal in the 400 meters with a time of 49.81 seconds, despite the heavy rainfall that occurred during the event.

About a month later, at the age of 30, Guevara participated in her fourth World Championships in Athletics in Osaka, Japan.

On January 16, 2008, she announced her retirement from all competitions due to conflicts with Mariano Lara, the then president of the Mexican Athletics Federation.

No help was received at that time from Carlos Hermosillo, director of the CONADE (Comision Nacional de Cultura Fisica y Deporte), who did not act rapidly and the problem only grew bigger and continued for months.

[2] At the end of her Senate term, she won a seat in the Chamber of Deputies in the 2018 general election, representing Sonora's second district for the PT.