BUENOS AIRES - Striker Diego Galvan scored the only goal in the 14th minute to give Estudiantes a 1-0 win over Nacional in the first leg of their Libertadores Cup semi-final in La Plata on Thursday. Captain Juan Sebastian Veron, taking a quick free kick in the centre of the pitch, found Leandro Benitez out on the right. The winger crossed into the middle of the penalty area where Galvan beat goalkeeper Rodrigo Munoz to the ball with a diving header into the net. The second leg is at Montevideo's Centenario stadium next Wednesday. Cruzeiro beat Gremio 3-1 at home on Wednesday night in the first, all-Brazilian semi-final in Belo Horizonte. Their return is in Porto Alegre next Thursday. Estudiantes, seeking a fourth title after their three wins in a row from 1968 to 1970, could have gone ahead in the eighth minute but Munoz parried a shot from Gaston Fernandez and then dived to save Mauro Boselli's effort from the rebound. The first half was dominated by the home side and Nacional's best effort, a header by defender Sebastian Coates from Nicolas Lodeiro's free kick, went straight to the arms of Palermo-bound Argentina keeper Mariano Andujar. Estudiantes started the second half with Matias Sanchez on for Veron who had suffered a knock after half an hour. Nacional, also three times South American champions, grabbed the initiative and in the 49th minute Santiago Garcia should have equalised. He ghosted in behind the defence to head a free kick from the left wide of the far post with Andujar beaten. Estudiantes gradually regained control but play was largely confined to midfield until near the end when Boselli might have added to their tally but Munoz stuck out a foot and deflected his shot.