River Plate on Tuesday beat Paraguay's Guarani 2-0 in the first-leg of the Copa Libertadores semifinal in Buenos Aires. Second-half goals from Gabriel Mercado and Rodrigo Mora gave the Argentine giant a promising lead ahead of next Tuesday’s return-leg in Asuncion. The winner of the two-game series meets either Brazil’s Internacional or Mexican club Tigres, which square off in the other semifinal first-leg on Wednesday, in the final. "It was a very tough, hard-to-pass match with Guarani playing well-ordered [soccer],” River Plate coach Marcelo Gallardo said. "It was a very good win for us because we scored two goals and did not concede one. We are on the right path.''