The Spanish full-back's effort - smashed into the bottom corner after a surge down the wing - was the side's third and perfectly sealed the result.
"I'm just glad we got the signing over the line because I had watched him quite a bit for Sevilla," Gerrard told Liverpoolfc.com of the defender.
"I had watched YouTube clips of him and I knew he was a flier, quick and very aggressive with and without the ball.
"He showed his aggression with the ball today with a terrific run and the finish at the end of it was just pure quality. If a Real Madrid or Barcelona player did that, everybody would be getting carried away. Give him credit - that was a top goal."
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