The Uruguay international scored twice and assisted with the third for Jose Enrique as the Reds registered only their fourth Barclays Premier League win of 2012.
"Luis is a very big part of the team. His first goal was a wonderful finish with a great weight of pass from young Raheem (Sterling)," said the Reds boss.
"He finished it great and for the second one there was a lovely pass from Enrique and a nice little off-the-shoulder run and finish.
"He is a master marksman, absolutely outstanding, and we are thrilled to have him."