The Welshman left Spurs for Real Madrid over the summer.
Redknapp told talkSPORT: "In the past, when they had Gareth Bale, he was such a fantastic talent that he would pull them out of trouble.
"There were lots of games where there were two minutes to go and suddenly a bit of magic from Gareth Bale and three points were in the bag. Well, they have lost that magic now.
"He was special. It has been difficult to replace him and that is a big problem for them."
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