The former Arsenal captain also praised Arsene Wenger, saying he owes nearly everything to the Frenchman.
The former Real Madrid midfielder moved to Arsenal for a club-record £42.4million fee in the summer but has seen his form dip of late, prompting questions to be asked of his consistency over the course of a full season.
But Fabregas, Arsenal's captain before moving to Barcelona in 2011, believes Ozil is one of the main reasons the Gunners are challenging for trophies this season.
"They [Arsenal] are doing very well and I am very happy for them," the 26-year-old told reporters. "I just wish them the very best.
"He [Ozil] is a good player. He's a very good assisting player, so he is one of the reasons [that Arsenal are challenging]."
The Barca man, who spent eight years in north London, also praised his former manager Arsene Wenger, revealing that he owes nearly everything to the Frenchman.
"All I can say are amazing words for Arsenal and Arsene Wenger. The most important figure to me was Arsene Wenger. I have to be grateful all my life to him and that's it.
"For me he is the most important person, he knows everything about me and that's the person that I owe nearly everything."
Is Fabregas right to defend Ozil's recent form?
image: © ins11thiago