The Brazilian, Willian Borges da Silva, has been Jose Mourinho's latest signing with hopes to strengthen Chelsea's midfield options.
Willian's arrival at Stamford Bridge has been preceded by the players Andre Schurrle and Kevin de Bruyne.
Although winger Victor Moses has left for Liverpool on loan, Oscar and Eden Hazard remain key players for The Blues, and Juan Mata has started only one Premier League game so far this season, following yesterday's 1-0 loss against Everton.
However, the Spain international is now in full shape and eager to play with has talented teammates.
"I think [the new signings] is very good for the club, for the squad and for the manager," Mata told Sky Sports. "I think they are really good - De Bruyne, Schurrle, Willian, they are quality young players.
"Each one has his different position, his different skills, but I think all of them can give us a lot and I think it is better to have a more complete squad. I wish we could play six together but it is not possible. But it is good for the club for all the competitions we have to face this season.
"I am very optimistic and positive. To be honest it has been a difficult position for me with an injury so I could train less than my teammates, but now I am feeling better and I am looking forward to playing.
"I will try to do my best like in the last two seasons and try to win and score and assist."
Mata was questioned about what Mourinho expected from him this season, and the 25-year-old replied confidently: "We spoke about it and he said I was very important for him and for the squad, so my aim hasn't changed.
"I want to be as good as I was in the last two seasons and even improve, to become a better player."
Mata said he wasn't focused on moving away from Chelsea during the transfer window, but he was focused on recovering from his injury.
The midfielder also paid tribute to the Cameroonian striker Samuel Eto'o, who has joined the Blues from Anzhi Makhachkala and will bring valuable experience.
"Samuel is well known everywhere, I think he can give us a lot. He scores and has a good character and I think for all the young players it is a pleasure to play with someone who has won a lot."
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