Spurs must overturn a 3-2 deficit next Wednesday to reach the group stage after Tuesday night's defeat at Young Boys.
“I think we are destined to be in the Champions League because the two chances they had at the end left me with my heart in my mouth,” Defoe said. “I am delighted Pav scored the second goal and I am confident we can win at the Lane. The second leg will be massive and it'll be a great atmosphere.
“We worked so hard last season to get to this stage and we don't want to throw it away. It is massive for the club and all we have to do now is win the game.
“We've seen enough to get at them. There was space in behind them but the early goal changed the game a little bit. Towards the end they got behind the ball and it is always difficult to break teams down when they do that. I thought we played well.
“The manager wasn't happy at half-time – he wanted a reaction and I think he got that in the second half. It was important to get the second goal.”