The 62-year-old says the forward was once the "jewel of Brazilian football" and has backed him to rediscover his best form during his loan spell at Stamford Bridge
The Corinthians-owned attacker joined Chelsea on loan until the end of the season in the January transfer window, but has yet to make his official debut for the Stamford Bridge side.
"It's a fantastic opportunity for him. You could even call it a golden opportunity," Zico told Chelsea’s official website.
"He's a player who has had ups and downs but he is a top-quality player and I think he will settle at Chelsea and do very well, which will also be very good for the national team.
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"When Pato broke through, he was considered the jewel of Brazilian football. He moved to Milan and was doing very well but then injuries came along and unfortunately he really suffered with them.
"Now he has another chance to prove his quality at Chelsea and get back to his best."
Zico was also full of praise for Chelsea winger Willian, who has scored twice in his last three games for the club.
"Willian is having an amazing season and is getting better all the time. It's great for the Brazilian people to see our players do well and enjoying success abroad and, of course, it also benefits the national team," he added.