The New Zealand international netted his first goal for the club, since his free transfer from Blackburn, in the win over Bolton on Tuesday night and Redknapp has said he will be trying to get him down to a new deal in the summer.
Nelsen signed a short term contract until the summer and the boss is anxious to get him committed to a longer term contract at White Hart Lane.
Spurs will now play Chelsea in the semi-final at Wembley after their win over Bolton, the game is scheduled for April 15th but Chelsea have requested that it be brought forward to help them in their preparation for a Champions League semi-final against Barcelona, if they qualify.
Redknapp said. ''I just think he is a great professional and a real good player. I couldn't believe I got him on a free. I felt it was an amazing player to bring to the club, he is a player I have chased for years.
''I have always thought he was top class, a great pro, a great trainer, a fantastic person.
''He has got a six-month contract. At the end of the season you have got to keep him here next year because he's worth his weight in gold just to have around for other people to look at the way he works, the way he trains, the way he behaves, his attitude.
''That's what football clubs are built upon, people like him, Scott Parker, Brad Friedel. You bring them in and it changes everything. That has been the difference this year."