Basel edged through in second place in Group B behind Real Madrid, and host Porto - who won H - in their last 16 first leg this week.
"The reality is that we want to be competitive and we will be," said Sousa, who won the competition twice as a player. "We want to be the team that has created Porto the most problems.
"With Porto there will be difficult moments for us, yet I am sure we will create them a lot of difficulties as well. We have to take risks and show personality.
"Porto has an identity, the same tactical structure, but Julen Lopetegui brought other dynamics to their playing style. I love to be here facing the best challenges because it makes me and my players grow."
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