Madrid: Atletico Madrid also took a huge step towards the semi-finals as goals from Antoine Griezmann, Angel Correa and Kevin Gameiro downed an under-strength Eibar 3-0 at the Vicente Calderon.
Despite largely empty stands amidst freezing temperatures in the Spanish capital, Atletico made light work of an Eibar side shorn of many of their usual starting line-up to ensure the return leg should be a mere formality.
"It was difficult in the first-half but you could see the chances would come if we were a bit more precise and that happened in the second-half," said Atletico boss Diego Simeone.
The hosts had the ball in the net on 25 minutes, but Stefan Savic was harshly adjudged to have been offside as he slotted home from close range.
However, Atletico had to wait only three minutes more to open the scoring when Jose Maria Gimenez beat Rodriguez to a free-kick lofted into the area and Griezmann headed the Uruguayan's knockdown into an empty net.
Rodriguez nearly redeemed himself in the second-half when Yannick Carrasco bore down on goal, but despite saving the Belgian's effort, the ball fell kindly for Correa to tap home the rebound.
Seven minutes later Atletico killed the tie off when Griezmann headed across goal from Koke's corner and the grateful Gameiro was left unmarked to nod home.