Redknapp says Amorim a squad full of quality from predecessor Erik ten Hag.
He wrote for The Sun: "It is actually the dream job and the perfect time to take on one of the biggest four or five clubs in the world.
"You see, if you’re at an all-time low, like United are now, there’s only one way to go. It was the same for me when I went to Spurs in 2008.
"I took over a side that was rock bottom, without a win after eight games, and where chins were on the floor. But I looked around on that first day and knew we wouldn’t be there for long.
"Not with the likes of Luka Modric, a young Gareth Bale, Jermaine Jenas, Aaron Lennon. Top talent all over the place.
"Alejandro Garnacho — a player I love — Kobbie Mainoo and Marcus Rashford would walk into most sides in the Prem.
Ruben Amorim showed flashes of a young Jose Mourinho is his latest press conference - and teased a big announcement
"Obviously results must improve and the manager will want to bring in one or two new faces and make the odd tweak.
"But we’re not talking a complete overhaul.
This isn’t the United David Moyes inherited when he replaced Sir Alex in 2013.
"One that may have been champions but — with all due respect — certainly wasn’t anywhere near their finest.
"Fergie got them over the line but so many players were nearing the end and a total rebuild was on the cards.
"It was nothing like the current squad, one which just needs a bit of fine-tuning. So ignore rubbish about how this season is already a write-off.
"With so many games left, if United go on a run — and there is no reason why not — they could get fourth spot."