The Slovakian international was praised for his performance during the Reds' 4-1 win over West Bromwich Albion in the Premier League on Saturday.
"I think the three at the back allows him to play to his strengths," he told the club's official website. "It allows him to defend, and it simplifies his game when we have the ball.
"I think in the run of games he has had, he has gained in confidence. I've recognised and acknowledged with him that he is playing at a really good level."
Liverpool are back in Premier League action on Saturday night when they make the trip to leaders Arsenal.