Playing for Chile Fed Cup team, Seguel has a win/loss record of 20–16. In 2006, her debut on the junior tour came at the age of 13. She played her first tournament at the first Open Junior International Chile, in May. There, she reached the quarterfinals, before losing to Argentinian player Ornella Caron, in straight sets. In 2007, she won her first singles title at the second Junior Open Chile, in October.

She has won eight singles titles and four doubles titles on the ITF Women’s Circuit. On 12 October 2015, she reached her best singles ranking of world No. 150. On 23 April 2018, she peaked at No. 163 in the doubles rankings. Playing for Croatia in the Fed Cup, Mrdeža has a win/loss record of 5–4.