Former U.S. Open champion Juan Martin del Potro was a straight-sets winner on Friday, as host Argentina leads the Czech Republic 1-0 in a best-of-five Davis Cup semifinal.

The 6-foot-6 del Potro, playing with a sore left wrist this week, handled Czech veteran Radek Stepanek 6-4, 6-4, 6-2 in the opening singles rubber on the red clay at Parque Roca in Buenos Aires. Del Potro smacked seven aces and was broken only once while piling up five breaks against the overmatched Stepanek.

Friday's second singles bout will pit U.S. Open semifinalist and former Wimbledon runner-up Tomas Berdych against gritty Argentine Juan Monaco.

Saturday's doubles rubber will pit Argentines Carlos Berlocq and Eduardo Schwank versus a Czech tandem of Ivo Minar and Lukas Rosol, while Sunday's reverse singles currently call for the world No. 8 del Potro to lock horns with the sixth-ranked Berdych and the No. 11 Monaco to take on the 40th-ranked Stepanek.

The Argentines are captained by Martin Jaite, while the Czechs are led by Jaroslav Navratil.

The Czechs are 3-1 all-time versus the Argentines, including a win in their last meeting in a quarterfinal in Ostrava in 2009.

Argentina lost to Spain in last year's World Group final in Seville, falling to 0-4 in Davis Cup finals.

The Argentina-Czech Republic winner will meet the Spain-United States victor in the final in November.