The Londoners turned to the 65-year-old at the weekend after dispensing with the services of Mark Hughes following a disastrous start to the season. They will arrive on Wearside having collected just four points from their first 13 games and rooted to the foot of the table.
O'Neill said: "He [Redknapp] is a very fine manager, he has proved that. The majority of us here in the room might well have thought he was going to be the next England manager, so well had he done at Tottenham Hotspur."
He added: "It wasn't to be, but he is a very fine manager and he will bring all of his experience to bear. He's back in football and he is a talented man."
Redknapp's return to the game coincided with unfounded rumours that O'Neill could be heading out of it again, although the Ulsterman has insisted he is going nowhere as he attempts to turn around a run of results which has not brought a surfeit of defeats, but not enough victories.
The Black Cats have managed just two league wins in their last 20 attempts, and have lost their last two at the Stadium of Light to Aston Villa and high-flying West Brom.
However, O'Neill has seen cause for optimism in recent weeks following a narrow defeat at Everton and a 3-1 victory at Fulham, although he knows their recent improvement will count for little if they cannot turn it into tangible results.
He said: "It's up to us to go to the game and play as strongly as we have done in the last number of games. We have been able to score six goals in the last three matches, so that's another positive for us.
"The league is very, very tight and very few points separate a lot of the teams at this moment, so as Southampton have proved, two consecutive wins put you right back in proper contention and for us, it is just a case of go and win at home."
O'Neill will give central defender John O'Shea and midfielder Lee Cattermole until the last minute to recover from the calf and knee injuries they sustained respectively against the Baggies, although both are major doubts.
Source: PA
Source: PA