Defoe was back with a bang against the Addicks with a double-strike to help fire Spurs into the FA Cup fourth round and set-up a trip to Fulham.
"It was great to see Jermain back and hopefully he'll have a good second half of the season," Redknapp told the Spurs website.
"He had the injury with England, missed a few months then came back and got sent off. He needs to kick-start his season now.
"If he can go on a run now and weigh in with 11, 12 goals - which he's capable of - it could make a big difference for us."