The Welshman joined Madrid for a record-breaking £85 million deal in the summer and has scored 10 goals and set up a further 11 in his first 20 La Liga appearances.
Fabregas says the former Tottenham star has significantly added the Blancos' quality as the two sides prepare to do battle at the Bernabeu.
The 26-year-old told Marca: “With him, they are stronger. Whether it is shooting, goals or offensive power, he brings a lot to the team and is definitely a good signing.”
The former Arsenal player insists Barca know how to play against Madrid and are in good condition as they head into the latest Clasico contest.
“We know how to play against Xabi Alonso, Bale, Karim Benzema and Cristiano Ronaldo," said Fabregas.
"Nothing is new. We see them every day and we know each other very well. We will not change our side but we must be brave, I want to see a team that attacks and keeps possession."
Fabregas then touched on the pressure facing coach Gerardo Martino after the club were forced to dismiss speculation that he would be leaving the club at the end of the season, as well as heaping more praise on Lionel Messi.
He continued: “Tata is very talented and capable of handling this pressure. He comes from the league in Argentina, where the pressure is enormous on the coaches and players. He won’t be surprised at all.
“Messi is the same as always. He is a very intelligent, skillful and physically strong player.”
Pep Guardiola recently claimed the Barcelona players were lacking motivation in his final season, but Fabregas is not in agreement.
“We have always wanted to win," he said. "I have not even heard the exact statements. I can only say that this group has always been motivated.
“Otherwise, it would have been impossible to reach 100 points in the following year. Without motivation, that achievement is impossible. Now we are still alive in all three competitions.”