The win moves the Blues to within four points of Manchester City in the Premier League table and Benitez was full of praise for his compatriot.
"He is playing really well," he said.
"Even without the ball he is working hard but when we are in possession he is making the difference, I always say the same; if the team are playing well these players can make the difference.
"I think the Premier League has a lot of good players and Mata is one of the best for sure - he can be even better.
"Mata is a player who is dangerous - inside the box and outside the box, we are really pleased with him.