Rangers' survival chances appear increasingly bleak, with Redknapp's men still rock-bottom of the Premier League and seven points adrift of safety after defeat to Manchester United on Saturday.
But the former Portsmouth boss remains convinced he can turn things around and will not be discouraged by the expected abuse he will receive from the Saints fans at St Mary's on Saturday.
Redknapp, who turns 66 at the weekend, said: "It is my birthday next Saturday and I thought there is no better way to spend it than getting 90 minutes of abuse at Southampton.
"They'll all be calling me 'Scummer' for my time at Portsmouth. I thought that would be a great way to spend my birthday!"
He added of the battle for survival: "There are enough games left - it is still wide open.
"We have got to go to Villa, we have got to go to Reading and we have got Wigan here. I still fancy us.
"We've got nothing to lose, everyone thinks we are gone. But you can change it so quickly.
"At Portsmouth in 2006 I had a crap team and we got 20 points from 10 games and stayed up. It ain't impossible."