ASUNCION, July 27 (Reuters) - Brazil's Internacional rode their luck to hold out for a goalless draw away to Libertad in the first leg of their Libertadores Cup semi-final on Thursday.
Libertad, quarter-final conquerors of Argentina's River Plate, twice struck the woodwork as they were foiled in their attempt to build a lead for next week's return in Porto Alegre.
Midfielder Pablo Guinazu hit the inside of the post from the edge of the penalty area in the first half after pouncing on a poor clearance by the Internacional defence.
Almost immediately, Cristian Riveros found Rodrigo Lopez unmarked inside the penalty area but he shot weakly at goalkeeper Clemer.
The Paraguayans came even closer with three minutes left when Riveros crashed a long-range volley against the underside of the crossbar.
The ball hit Clemer on the back as it rebounded but bounced harmlessly out of play for a corner.
Internacional had plenty of possession and left-back Jorge Wagner was twice close with powerful long-range shots in the first half. The first was blocked by a team mate and the second tipped over by goalkeeper Hector Gonzalez.
Winger Rafael Sobis was a constant menace to Libertad, forcing a good save from Gonzalez with a shot on the turn and shooting narrowly past the upright midway through the second half.
Neither side have won the competition before.
The winners will meet either defending champions Sao Paulo of Brazil or Guadalajara of Mexico in the final. Sao Paulo won 1-0 away in the first leg on Wednesday.