I couldn't focus on our game too much as the City-Spurs on the other screen was just too engrossing, but having rewatched the extended highlights it's noticeable that Porto played so differently from the way PL teams set up against us. In defense, they let us counter-attack with more space and time that any PL team in probably over one and a half seasons. In attack, they also threw more numbers forward than we usually see against us. I often talk about the league "adjusting" to the leading teams – so we've been playing against some variation of collective "anti-Liverpool" tactic for many months and here Porto were just playing their game and it was kind of awkward for us to adjust to when we had to defend, but also gave our attackers much more joy, similar to our CL run-in last year.
My point is that CL is such a different competition – even teams from the same league like City and Spurs played a totally different game than they would have if it was in the PL. This could work to our advantage as Barca and, say, Ajax in the final if we get there, will make the sort of mistakes and almost naive tactical decisions that PL teams who watch us every week never give us the luxury of. At the same time, our defense will be tested by unfamiliar attacking patterns; they surely don't get to face Messi every week, much less Messi+Suarez and Coutinho/Dembele etc.