Having joined United as a player to inspire them to promotion in 1982, Keegan made a marvelous return as a manager during his first spell in the dug-out which ended 11 years ago.
Harper: "When we look back we might look at that game and say that was the spark that ignited everything.
"That was the moment the new Kevin Keegan era really began in earnest. I certainly hope so.
"It was absolutely brilliant, fantastic. It was as good a team display as I've ever been involved in. It's been a long time coming, but I can't remember a team during my time here playing as well as that away from home.
"It was different class. I think we got a big boost when we arrived at the ground and saw Tottenham had changed their shape to try and match us. It meant they were worrying about us and what we can do. It's all credit to the manager for changing the formation a few weeks ago because it has worked.
"To go to a club like Tottenham and win so convincingly is a big achievement. They've been in good form, they've won the Carling Cup this season and they have a top manager.
"I think teams will be worried about us now, if Tottenham were, then so will all the teams in the division. A result like this will certainly make people sit up and take notice."
"When the manager returned to the club I was quoted as saying fasten your seatbelts because it was going to be an exciting ride.
"It has taken a little while to get going. It's been a difficult time for us all and difficult for the manager because he wasn't able to bring anybody in during the transfer window. He has been looking at what he has got and how best to use it, but we feel it is coming together.
"We went behind at Birmingham City as well. But we responded to that in the right way, we came out and turned the game around in the second half and got the point.
"Maybe that was when things began to shift and the momentum came our way. We've followed that up with two back-to-back wins against Fulham and Tottenham and the confidence has returned.
"People might have thought he was mad to go to Birmingham with a formation like that, but that trio of Obafemi Martins, Mark Viduka and Michael Owen will worry anybody and that is what they have done.
"We've shown what a good team we could be with the right additions in the summer. That is what the manager had challenged us to do and hopefully this is only the beginning. You know, we're not safe yet, we've got some work to do, but the whole place feels a lot better than it did."