|Mourinho's men finished third in the league last season, four points adrift of champion Manchester City.|
The Londoners have added Fabregas, Diego Costa, Argentina world cup jersey Didier Drogba and Filipe Luis germany world cup 2014 jersey to their squad in the close-season after losing the likes of David Luiz, Ashley Cole, Frank Lampard and Romelu Lukaku.
But the signing of former Arsenal captain Fabregas is the biggest for Mourinho, who believes the midfielder is just what Chelsea were missing last season.
"He can play as a number eight or number 10, plus the fact he has experience in the Premier League," Mourinho said.
"He is not on the foreign list, as he counts as a homegrown player, which was important and he is not on the foreign list for the Champions League either. They were important factors.
"I see him everywhere because he can play everywhere. His best quality is the speed where he analyses the game and executes.
"He is difficult to shake off the ball or make the wrong decision. He can accelerate the intensity of the game or he can reduce it. He's very intelligent. And he has goals. cheap soccer jerseys He is the missing piece for us."
The Chile star played 74 minutes as Arsenal lost 1-0 to Monaco in the Emirates Cup, having come off the bench during a 5-1 demolition of Benfica a day earlier.
Alexis, who joined from Barcelona last month, is keen to settle as soon as possible and believes his game time over the weekend will prove hugely beneficial.
"I have to go step by step, I have only trained twice with the team," he told the club's official website. "Today I played 70 minutes, I believe I needed it, and I just have to keep on working hard and training.
"I like this style of football. What is important for me now is to try to play games, to score as many goals as possible and to win titles.
"What is important now is to play and get fit. I need to get 100 per cent."
The 25-year-old also thanked Arsenal's fans for his warm reception.
"Of course I loved it, I am extremely thankful to all of them," Alexis 2014 world cup jerseys added.
"I am extremely happy and I hope I can make them very happy as well."