Despite not hitting the heights of the 8-0 thrashing dished out to Aston Villa on Sunday, Chelsea were the better side in a game that lacked any sustained quality. Mata struck from 25 yards in the 38th minute to condemn Norwich to a second defeat in four days.
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," the Chelsea boss said. "Even without the ball he is working hard but when we are in possession he is making the difference."
Benitez added: "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.
Benitez left Frank Lampard on the bench for the trip to Norfolk amid speculation he will leave Stamford Bridge next summer. But the former Liverpool boss was bullish about the future of Lampard and fellow England star Ashley Cole.
"From my position it is very easy, it is a private conversation between Frank and the club and that is it. He is a good player and I would like to bring the best from him, that is my position. I don't know if Ashley has had the conversations or not but, for me, they are players under contract, good players."
Norwich boss Chris Hughton was pleased with the endeavour shown by his side to limit a talented Chelsea team to only a few chances.
"I thought we dealt with them for really big periods of the game, the chances they had I thought were fairly minimal, we restricted them," he said. "As the game opened up in the second half I think we broke very well and showed good energy and might have got a draw in the end."
Mata's goal came after Norwich had gifted the ball to Chelsea and the Spaniard had missed a chance only minutes earlier after David Luiz had won possession from Wes Hoolahan. And Hughton added: "The area I was disappointed in during the first half was that, we have been good on the ball, but we were a little bit loose.
"It allowed them to have three or four good counter-attacks. We dealt with them eventually very well but it was a ball that was given away (that led to the goal), they broke very well and we got bodies around the ball but I think you have to admire the strike."