BUENOS AIRES, Argentina (AP) Rising star Dominic Thiem of Austria has knocked former top-ranked Rafael Nadal out of the Argentina Open with a 6-4, 4-6, 7-6 (4) victory over the defending champion on Saturday.

Nadal had a match point at 5-4 on clay in the final set of the semifinal but failed to convert.

Nadal is ranked No. 5 by the ATP and Thiem is No. 19.

The 22-year-old Thiem will be looking for his first ATP singles title of the season in Sunday's final against Nicolas Almagro of Spain. Almagro defeated countryman and second-seeded David Ferrer in the other semifinal 6-4, 7-5.

Nadal, who used to be nearly unbeatable on clay, now heads to Rio de Janeiro for next week's Rio Open, where he lost last season in the semifinals to Fabio Fognini of Italy.