The England midfielder told fans during a Google Hangout that he felt the loss of the club captain in the aftermath of his move to Barcelona.
"I was really upset about Fabgregas leaving," he said. "He was the captain and you always went to him if you had a problem."
But the 21-year-old is now looking forward to a bright future with Arsenal, which currently sits four points clear at the top of the Premier League, and reserves special thanks for manager Arsene Wenger.
"He gave me a chance when I was 16 and brought me into the first team," Wilshere said. "He picked me out and gave me that chance to train with the first team. He put his arm around me. Some games I didn't play well but he still stuck with me. When you're young you do make mistakes."
Wilshere, who scored twice during the 2-0 Champions League victory against Olympique de Marseille on Tuesday, will be hoping to start for the Gunners once again when they take on Cardiff City in the Premier League on Saturday.