The former Middlesbrough boss led the Rams to the Championship playoff final in his first season in charge, where they lost to Redknapp's side.
McClaren has had difficult spells in charge of England, Nottingham Forest and FC Twente in recent years.
"I'm delighted for Steve McClaren. OK, he's lost the game but he has rebuilt his reputation, hasn't he?" the Derby Telegraph quotes Redknapp as saying.
"He is a fantastic coach. I didn't realise that before, having not previously worked with him and not knowing him that well but when he came in and worked with us at the start of the year, I was so impressed with him.
"To see what he has done at Derby is fantastic. Saturday was a bad day for him but overall in football he's on his way back. That's for sure and I'm pleased for him."
McClaren was part of Redknapp's coaching staff at Loftus Road before leaving in September to join Derby.