BUENOS AIR: Austria’s Dominic Thiem backed-up his shock semi-final win over Rafael Nadal to clinch the Argentina Open title on Sunday with a 7-6 (7/2), 3-6, 7-6 (7/4) victory over Nicolas Almagro. Thiem, the world No 19 and the youngest player in the top 20, captured his fourth career title all of which have been on clay.