The Londoners ended the Whites' giantkilling FA Cup run with a 3-1 fourth-round replay win at Elland Road courtesy of Jermain Defoe's third hat-trick of the season.
But United had made an impression on a relieved Redknapp. "We came to Elland Road, probably the first time for some of my players. The atmosphere the fans created was just incredible," Redknapp said.
"Leeds are a good side and they'll certainly go up this year and I can see them being back in the Premier League in the next few years."
He added: "This is a massive football club. It's really a Premier League club and it needs to get back where it belongs."