BUENOS AIRES (AFP) - 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.

The 22-year-old claimed trophies on the surface at Gstaad, Umag and Nice, all last year.

Thiem had made the final by seeing off Nadal 6-4, 4-6, 7-6 (7-4) on Saturday, saving a match point in the process.

Almagro, 30, was the champion in Buenos Aires in 2011.