Bayern boss Guardiola wary of Porto pace
Bayern, champions in 2013, were paired against Porto - winners in 2004 under Jose Mourinho - in Friday's draw in Nyon.
It is a repeat of the 1987 European Cup final, which the Portuguese outfit won 2-1.
"All teams have a special quality," said Guardiola, who has won this competition three times with Barcelona - once as a player and twice as coach.
"Porto and Shakhtar [Donetsk, Bayern's last 16 opponents] were in the same group, so we have already watched a few of their matches.
"Porto have a great team and a beautiful stadium. They are very strong physically and attack with a lot of pace, but in the quarter-finals you can't expect an easy match."
Bayern goalkeeper Manuel Neuer added: "The atmosphere in Porto is very heated.
"I witnessed the Porto fans during the 2004 Champions League final against Monaco. The atmosphere was amazing.
"With these fans it won't be easy for us, but we have played in many different stadiums with varying atmospheres and we will know what to expect."
Vitor Baia, who played in goal for Porto during their 3-0 triumph over Monaco in the 2004 showpiece, concedes his former club could have been handed an easier draw.
"Bayern were one of the least desirable opponents, but nothing is impossible − the tie starts 0-0," he said.
"Last time we came across Bayern [in 1987] we also weren't favourites, but we won. On a perfect day with a perfect game, anything can happen."