Carlos Berlocq and Leonardo Mayer led Argentina to a victory Sunday over the United States on the first day of play at the World Team Cup.
The tournament, which features two groups of four nations in round-robin play, serves as a final tuneup for the French Open, which starts next Sunday in Paris.
Berlocq cruised to a 6-2, 6-2 victory over Andy Roddick in just 90 minutes after Mayer had given the Argentines the first point of the day with a 6-4, 5-7, 6-3 triumph over Ryan Harrison. Rain halted the doubles match with the Argentine tandem of Berlocq and Juan Ignacio Chela holding a 7-6 (7-2), 4-1 advantage over Harrison and Blake.
Argentina and the United States are joined in the Red Group by Japan and the Czech Republic. Tatsuma Ito gave Japan an early edge Sunday with a 3-6, 6-4, 6-4 win over Radek Stepanek. Japan and the Czech Republic will continue their set on Monday when Go Soeda meets Tomas Berdych followed by an undetermined doubles match.
In Blue Group play, defending champion Germany opened a 1-0 lead over Russia thanks to a 6-0, 6-2 rout for Philipp Kohlschreiber over Alex Bogomolov Jr., and Serbia has a 1-0 edge over Croatia after Viktor Troicki notched a 6-3, 7-6 (7-3) win over Ivan Dodig.
Germany's Florian Mayer will battle Igor Andreev of Russia on Monday before a yet to be announced doubles match, while Janko Tipsarevic of Serbia will square off against Croatia's Ivo Karlovic before a doubles match concludes that opening series.
Last year, Germany won a record-breaking fifth title with victory over defending champion Argentina.