Defoe admits the performance in Italy was not acceptable, but he insists the team are still confident of making the final in Amsterdam and lifting the trophy.
"We're disappointed as professionals," he said. "Even though we're through, we're not happy at losing like that.
"But we still don't have to take any steps to join the top sides because in the first leg we were so much better than them.
"There could have been a lot more goals at White Hart Lane.
"Last night was difficult, but we have done so well all season and we don't want to let it slip."