Playing in his first match since being upset in the first round of the Australian Open, the top-seeded Kuerten was ousted in opening round Tuesday at the $425,000 AT&T Cup.

The Brazilian and defending champion had no answer for local favorite Agustin Calleri, who used his home country to his advantage en route to a 6-3, 6-7 (5-7), 7-6 (7-4) upset.

In the first Grand Slam of the year, Kuerten was beaten last month by unknown Frenchman Julien Boutter.

It also was a quick exit for second-seeded Argentine Guillermo Canas, who was beaten by Spaniard David Sanchez, 6-2, 6-3.

Third-seededed Nicolas Lapentti of Ecuador made it out of the first round with a 4-6, 6-1, 6-3 victory over Argentine Leonard Olguin.

A pair of Spaniards -- fifth seed Felix Mantilla and sixth-seeded Alberto Martin also advanced. Mantilla took out countryman Fernando Vicente, 7-6 (9-7), 7-6 (7-3), while Martin bested Argentine Marian Puerta, 7-6 (7-5), 6-1.

In matches of unseeded players, Nicolas Massu of Chile defeated Argentine Gaston Etlis, 6-1, 6-4; Marian Zabaleta of Argentina outlasted American Hugo Armando, 6-7 (2-7), 7-5, 6-3; Spaniard Feliciano Lopez beat Luis Horna of Peru, 3-6, 6-4, 6-3; Argentine Franco Squillari disposed of countryman Sebastien Prieto, 6-1, 6-2; and Fernando Gonzalez of Chile got by Chilean Galo Blanco, 7-5, 2-1 (retired).

The champion earns $55,000.