The midfielder was appointed club captain after Celtic legend Scott Brown left the club at the end of last season’s disappointing campaign.
There was scepticism around McGregor becoming the Celtic captain and many felt that while being an excellent player, he lacked the heavyweight personality to lead the Scottish giants.
But McGregor has been excellent at the start of the season and has led by example with some brilliant performances on the pitch under new manager Ange Postecoglou.
Ferguson admits McGregor’s game performances and game have gone up a level since he became captain at Celtic Park.
He stressed that the midfielder has shut the naysayers up through the sheer weight of his performances as Celtic captain.
Ferguson said on the Go Radio Football Show: “Certainly I think Callum McGregor has taken his game up to another level since he has been named captain.
“Callum has taken the captaincy really well and a lot of people were really questioning whether that would be the right idea.
“But he has proven it with the performance he has put on for Celtic.”
A product of the Celtic academy, McGregor has made more than 330 appearances for the club since breaking into the team.