The Portuguese champions have won their first four matches in the league, a run that has taken them two points clear of Sporting Lisbon in the table.
Vienna, who beat Dinamo Zagreb in the final round of qualifying, have had a rocky start to their title defence thanks to three draws and two defeats from eight games.
The sides met in the competition back in 2002 when Porto earned a 3-0 aggregate victory in the second round.
Porto coach Paulo Fonseca has rubbished the suggestion that his side will start as strong favourites when they open their Champions League Group G campaign against debutants Austria Vienna on Wednesday.
While Porto will kick off their 18th Champions League campaign in the Ernst Happel Stadium, their opponents squeezed through to the group stage for the first time after a tense play-off win over Dinamo Zagreb.
And the form of both sides could hardly be in greater contrast heading into the game, with Porto sitting on top of the Portuguese Liga with maximum points from four games, while Vienna are fifth in the Austrian Bundesliga and without a win in their last two.
But Fonseca said: "We are not playing at home and we are facing opponents who have reached the Champions League on great merit. We do not have an easy task.
"The importance of winning this game has more to do with the fact that it is important to start off well in the group stage. We can only prove that we are favourites with what we do on the field."
Fonseca does not expect to make any major team changes for the tie in Austria as his side look to get off to a dominant start in a group that also includes Atletico Madrid and Zenit St Petersburg.
Fonseca's opposite number Nenad Bjelica has admitted his side face a major task against opponents he classes as "incredibly strong".
Vienna: Lindner; Ortlechner, Suttner, Koch, Rogulj; Mader, Holland, Royer, Syankovic; Jun, Hosiner
Porto: Helton; Otamendi, Danilo, Sandro, Maicon; Defour, Lica, Fernando, Quintero; Varela, Martinez
