The German coach reminded reporters of Liverpool's thrilling 4-3 win over Premier League leaders Manchester City in January, adding that his players are capable of producing such a performance on the European stage.
"I know it already we can compete with them, I don't have to look at them," Klopp said. "I think probably the strongest football team in this moment in Europe is Manchester City and we played them twice already at the highest level.
"The Premier League is a little different but if we meet [City] then we could beat them. That is how it is. But it is not important right now. We are in Porto and that is the only thing.
"We can make one mistake, that is how it is in life. And of course we as a team we will never do that."
Liverpool's tie with the Portuguese side is their first in the knockout stages since 2009.