Former British, European and world featherweight champion McGuigan showered praise on Cleverly in his column for the Daily Mirror newspaper, but also urged caution.
"Let's not burden Welsh wonder Nathan Cleverly with the label of the new Joe Calzaghe," he said.
"It is enough that he enters phase two of his professional career as the British and Commonwealth light-heavyweight champion.
"He is beautifully built for the division, standing 6ft 3in with long levers [arms].
"In his early days he sparred with Calzaghe, which was brilliant exposure, allowing him to develop a feel for the game at the top level.
"Though his record shows only six KOs in his first 16 bouts, the last three all ended early, indicating that he is learning how to harness power through timing and use of the feet.
"He likes to trade in the trenches and he has fast hands, throwing punches in clusters."
*Listen to Cleverly and McGuigan's views on him on BBC Radio Wales' The Back Page on Saturday, 18 June, 0830-0900 BST then on demand on iPlayer
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