Van Dijk strolled through his two-year spell in Scotland before departing for Southampton with two Premiership titles and a League Cup winners' medal.

But even those classy displays are not enough to top the contribution of skipper Brown in McGregor's eyes.

Asked to name the best player he has played with during a Q&A session on Celtic's Twitter account, McGregor opted for his current midfield partner.

"The best player I've played with is a tough choice," he admitted. "I've played with Virgil Van Dijk who is now regarded as the best centre-half in the world.

"He's progressed so much since leaving Celtic – but the person I see perform at the highest level every single day is Broony.

"He does it every day in training and in games. His mentality is always the same. For me to work so closely with him, I see his attitude and the way he drives other people on.

"He's always got the highest standards. His footballing ability gets overlooked a lot as well. You don't play for Celtic for over 10 years and wear the captain armband and not be a top player.

"He's played in all these European games and he's a top footballer as well. For me, to be that consistent over a period of 14 or 15 years shows that he's a top player."

While that question proved a close call, McGregor insists there is no debate about the toughest opponent he has faced.

He said: "I'll go for an easy one here and say (Lionel) Messi. It's a standard answer but he's so good that you can't help but pick him every time.

"You watch him on the TV and he's incredible. To play against him a few times is something else. He's so good that you can't even get near him.

"You think he's going to pass it and then he dribbles past you. It's like he knows what's going on before you even think about what he's going to do. He's incredible and such a special talent."

McGregor was part of the Celtic youth team trained by the late Tommy Burns, and the Scotland international admits he would loved to have lined-up alongside his mentor.

"He was incredible and such a massive influence on me when I was younger with him being head of the academy," he added.

"He was always working really close with the academy even when he was first-team coach.

"My Dad remembers watching him play and would tell me how good a player he was. He was similar to me in that he was left-footed, could shift the ball, ping passes and score goals.

"If I could choose another ex-Celt to play with, I'd go with Henrik Larsson. As a midfield player, he'd make my job so easy. You'd find him with the ball and he'd do the rest. He could do everything, come short, run in behind or score headers."