Benitez has had a tough introduction from the Chelsea fans since replacing popular Champions League winner Roberto Di Matteo a little over a week ago.
Dropping Mata, who has scored four goals and set up another six in 12 Premier League appearances this season, for Ryan Bertrand also did not go down well with the Stamford Bridge faithful.
However, speaking to reporters ahead of Saturday's Premier League trip to West Ham United, Benitez said he wanted to rotate the squad to keep players fit and fresh.
"My idea is to use the squad, we have too many players playing almost every game, so we have 11 or 12 playing almost every game, and the other players didn't have too many minutes," the Spaniard said on Friday.
"So we will try to fix this, you cannot play two, three games in eight days and be fully fit.
"You lose some pace, you lose some energy, so you manage the squad, we have quality, so you can manage the squad and give some minutes to every player, especially now we have Japan [for the Club World Cup]."
Chelsea have nine matches in December, when, as well as a typically crowded Christmas fixture list, they travel to Japan for the Club World Cup.
DYNAMIC FORM
Mata, who scored Spain's final goal in the Euro 2012 final victory against Italy, has been in dynamic form this season, and Benitez said he had a major role to play as third-placed Chelsea look to close the gap on Manchester United and Manchester City at the top of the table.
"He is one of the best players, for sure."
After scoreless draws with City and Fulham, Benitez is looking to kick-start his reign against London rivals West Ham who have lost their past two matches.
He will be without John Terry (knee injury), Frank Lampard (calf) and Daniel Sturridge (hamstring) while England centre half Gary Cahill returns in place of the suspended Brazilian David Luiz.
"Defensively we've looked really good in the last two games," said Cahill. "The new manager has come in and organised it so we're not as open.
"He's changed the mindset of the players when they haven't got the ball, that's the main thing.
"At the start of the season we did it well and had a balance in the team and kept clean sheets while scoring goals but we lost our way especially at Juventus where we were so open," said Cahill referring to last week's 3-0 Champions League defeat.
"There's no way we can keep clean sheets like that so the mentality of getting back into a good shape when we lose the ball has returned, making sure everyone is the right side of the ball."
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