The Saints take on Turkish club Eskisehirspor in the second leg at McDiarmid Park following their 2-0 loss last week but Frenchman Tade, who missed that match due to injury, believes the deficit can be overturned.
“I am always positive. There’s no defence in the world that cannot be cracked,” he said.
“Barcelona are the best team in the world, but they still didn’t win the Champions League or La Liga.
“Lionel Messi is the best player in the world, but he missed a penalty at a crucial time against Chelsea. In football anything can happen.
“I’m sure Eskisehirspor have conceded goals before and we will have a go to make that happen here.
“We have belief because if you don’t believe you would be as well staying at home.
“I have learned in Scotland that you always have to have confidence in yourself.”