Mata faces his biggest test since joining the Blues this summer when red-hot Barclays Premier League leaders City visit Stamford Bridge. Roberto Mancini's unbeaten side have dropped just four points in their opening 14 games, thrashing title rivals Manchester United and Tottenham away from home along the way.
But their remarkable form has failed to unnerve Mata, who said: "As a player, you have respect for Barcelona but you never have fear. So, no, we do not have any fear of City, especially because we're playing at home. We do have the ultimate respect for them because they're the league leaders but fear? Not at all."
Fifth-placed Chelsea go into the game 10 points behind City and even victory would still leave them looking for other teams to do them a favour if they are to reel in the leaders.
Mata said: "It is very difficult that they (City) will win every game, as they are doing at the moment. So for us and the other teams, we just have to hope that they stop winning."
The 23-year-old added: "They have a big points difference, but I think it is not impossible. If we win against City, we will have more confidence.
"The Premier League does not finish for another six or seven months. Nothing is impossible."
Mata will be key to Chelsea's hopes and beyond in what is proving a stellar first season in England for the Spain star. He admitted he was surprised how quickly he had adapted to his new home and suggested English and Spanish football were not as different as many believe.
"We are allowed to play like we are in Spain, with more possession, more passes, more assists, and here everything is normally different to that," he said.
"A lot of Spanish players have come here in the last few years and that is good for the Premier League, to have different styles of football."
Source: PA
Source: PA