The 66-year-old managed the young forward for several years at Tottenham before then taking him on loan at Loftus Road last season, where he flourished despite the Rs' relegation.
"He was fantastic for us in the time he was at Rangers," Redknapp told the Sunday Mirror. "I think it was the making of him.
"He showed that he get the better of a number of Premier League defences. I also decided to switch him. He was always on the left but I decided to play him on the right and he made an even bigger impact.
Townsend has started eight of Spurs’ 12 games so far this season, finally breaking into the first team at White Hart Lane, but Redknapp does not feel that he waited too long to give him a taste of the Premier League.
"Yes, I let him go on loan a lot while I was Spurs boss] but that was because I had Gareth Bale and Aaron Lennon as my regular wide players at Tottenham," he argued. "I took Andros to Europa League matches but he wanted to be playing on a regular basis
.