The Portsmouth manager, 60, has just signed a new three-and-a-half-year deal to stay at Fratton Park until 2011 - when the south coast club plan to open their £600million, 36,000-capacity new stadium at Horsea Island.
And Redknapp insisted: "I'm certainly not going to say this is my last contract. Why should I?
"When I finish this one I'll still be two years younger than Sir Alex is now. And I'll still look younger than him.
"Why should I call it a day? I love being manager here. So does Fergie at United and he'll stay there as long as he wants because they always win.
"That's what I've always got to aim to achieve here - even though top teams always have the top players. Let's face it, you can sign a contract for 20 years and still get the sack at any time.
"But, yes, I'm delighted the owner (Sacha Gaydamak) has given me a new deal, even though I've still got 18 months to go on the old one. He has always backed me and he's really ambitious for the future of the club.
"It took me about a minute and a half to agree to the terms of the new contract."
But he said: "We are close now and with any luck we have as good a chance as anybody of going all the way."