The 1974 World Cup winner says he has no doubts about the Turkey international's ability to shine at the Santiago Bernabeu, but believes patience is the key if he is to flourish.
Speaking to AS on Thursday, the 67-year-old, who also had a three-year spell between 1973 and 1976 with the club, is adamant the summer signing from Bundesliga champions Borussia Dortmund will eventually showcase his talents regularly.
"Sahin is a very, very interesting player who is very good," said Gunter. "[His success at] Borussia was the key.
"[Real Madrid must] give him some more time, a year or half-a-year, because he will become an important player for Real Madrid in the future."
"He is a very technical player, with great variety in his passing range, tactical awareness and high work-rate."
Netzer also offered his opinion on the form of Real Madrid's German pair of Mesut Ozil and Sami Khedira, playing down the former Werder Bremen attacker's dip in recent performances, and reserving special praise for Khedira's back-to-basics approach.
"It is normal [for Ozil] to have a dip in his performances," he continued. "No-one can always be 100 per cent in top form all the time. He is young and has to learn.
"Now playmakers are also required to put in a lot of effort. For Germany he had to work very hard, but Ozil has not reached the top of his career yet, I can assure you.
"[Regarding Khedira], he is an ideal player for a coach. He runs many kilometers, offers balance, isn't complicated, but is very useful," concluded Netzer.