Defoe made his first start in the Barclays Premier League since early October in place of the injured Rafael van der Vaart.
He linked up well with two-goal Emmanuel Adebayor as Tottenham took their points tally to 28 from the last 10 games to maintain their push for a Champions League spot.
Redknapp said: "We lost Rafael with a hamstring injury but Jermain has been in fantastic form.
"We had a reserve game on Tuesday and he got five goals against Charlton and he looked so sharp.
"Some of his play in the second half today was fantastic."
Redknapp added: "Jermain has been unlucky. I can only play him or Rafa who has played well and scored goals.
"He had that run of five or six goals in five games so it has been difficult for Jermain and I felt sorry for him.
"I told him that but there was nothing I could do. I've got Adebayor and one to play with him."