Jean-Claude Darcheville, who had earlier spurned a great chance, collected Steve Davis' cross to slot the ball past goalkeeper Rui Patricio after 60 minutes.

Liedson struck a post for Lisbon as Vukcevic and Veloso also went close.

But Rangers' defence held firm and Steven Whittaker's solo effort in the 90th minute secured a last-four clash with Italian outfit Fiorentina.