The England striker was on the scoresheet in the 3-1 win.
"We controlled the game throughout and it was a typical cup-tie, we had chances, hit the crossbar twice and the keeper made some unbelievable saves in the first half," Defoe told the Spurs website.
"They then got one chance and scored!
"Even then you have to be positive and think you are going to get the goal and once we scored, I knew we would get another.
"The manager said to us, 'just get the first goal' and we knew the second and third would follow.
"I’ve always said every game is difficult, no matter who you play against, but once we scored that first goal I knew we’d go on to win the game."