Pirlo parted company with the Rossoneri last summer before joining the Bianconeri on a free transfer and has since gone on to play a key role in the Turin outfit's resurgence under new coach Antonio Conte.
Gattuso insists that he is not in the least bit surprised by his former team-mate's performances for Juve, hinting that the deep-lying midfielder should never have been allowed to leave San Siro.
"Pirlo has been and is a great player," the former Italy international told Il Corriere dello Sport. "He is still showing it. There are not many champions of his calibre."
Gattuso's skipper, Massimo Ambrosini, also admitted that Pirlo is still missed at Milanello.
"Pirlo carried a certain weight in the dressing room in terms of decision-making and spirit," the veteran midfielder revealed. "He's a champion who will remain forever in our hearts."
While Gattuso is still recovering from an eye problem, Ambrosini is expected to line up against Pirlo on Saturday night as Milan host Juve at San Siro in a crucial Serie A clash.
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