Inter are second in Serie A having won three of their last four domestic league matches but face a Porto side with 10 consecutive victories in all competitions so far this year.
"As far as favourites and predictions are concerned, I’m not very good," Inzaghi told reporters. "...we respect them (Porto) a lot. They always or almost always manage to make it to the knockout stages... We are confident and in good shape."
Inzaghi will face Porto coach Sergio Conceicao (48), his old Lazio teammate with whom he won the Italian Cup in 2000.
"Sergio, I'll see him again with great pleasure. He was a great teammate with whom I shared victories at Lazio. He’s a great coach, he’s doing great things. He plays physical and technical football," Inzaghi said.
He added that striker Romelu Lukaku (29), who converted a penalty in Saturday's 3-1 home win over Udinese, and midfielder Marcelo Brozovic (30) are both returning to full match fitness.
"Both of them are physically very well. They are recovering. Brozovic has been out a lot and now he’s raising his minutes, and against Udinese he played 65 minutes in the best way.
"Whoever doesn't start will be fundamental in the match in progress because in these matches 95 minutes matter."
Porto are second in the Primeira Liga with 51 points, trailing leaders Benfica by five after 21 games.
