Callum McGregor played with Liverpool defender Virgil van Dijk at Celtic.
McGregor played with Van Dijk at Celtic during the two years the Netherlands international defender was at the Hoops.
The 27-year-old centre-back joined the Hoops from Groningen in the summer of 2013 and left for Southampton in the Premier League in the summer of 2015 for a transfer fee reported by BBC Sport to be worth £13 million.
The Dutchman is now at Liverpool, and the defender is one of the best in his position in the world.
Van Dijk’s performances at the back have been key to Liverpool reaching the final of the Champions League as well as taking the Premier League title race down to the wire this season.
Celtic star McGregor has raved about the 27-year-old, and he has been hugely impressed by the progress that the central defender has been since he left the Hoops.
McGregor told The Scottish Sun about Van Dijk: “When Virgil played up here he strolled it every single week. When he left the boys knew he would do well.
“It is always difficult when you come from Scotland to make that jump straight away due to the perception of the football here. Teams look and don’t really know.
“Players have to take that middle step to prove they can play in the Premier League. But within a season or two Virgil has become the best defender in the world.
“Nobody can doubt that fact. He has been outstanding in every game I have seen them play.”
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