"He's been excellent. He's kept 10 clean sheets this year," said the former Red.
"Look at how many keepers Liverpool have let go in the last few years who are still playing in the Premier League, but this man has managed to make the position his own and is one of Rafa's great buys.
"I knew about Pepe from my time in Spain, where he had a very good reputation because he was excellent over there. Now he's fantastic for Liverpool."