Redknapp has been delighted by the attitude of his 14-goal striker, on-loan from Manchester City.
"He has done ever so well for us. He has not been a minute's problem," Redknapp said.
"If you've got one or two bad apples they can just ruin everything for you. I think that's where we were lucky again this year. We changed things around and the people I brought in made a big difference to the club.
"There is no-one like that here. They are good lads. That's been the difference.
"They have been key signings for us. We changed things around a bit and Manu has come in and done the same."