Lucho Gonzalez scored the only goal of the night as Porto ensured Austria Vienna's debut in the Champions League group stage ended in a narrow defeat.
Gonzalez found the target 10 minutes into the second half as Porto made the perfect start to their Group G campaign.
Hosts Vienna had their moments at the Ernst Happel Stadium, with Marko Stankovic unlucky to see his second-half header hit the post, but better will be needed if they are to avoid becoming also-rans in a group also containing
Atletico Madrid and Zenit St Petersburg.
Porto had the best of what chances there were in an uneventful first 45 minutes, and just 80 seconds were on the clock when they forced Heinz Lindner into a good save from Francisco Fernando's volley.
With 28 minutes gone Jackson Martinez spurned a glorious chance to put the visitors in front when he flashed wide from six yards.
Vienna, who earned their maiden group stage appearance after a tense play-off win over Dinamo Zagreb, enjoyed good spells of possession in the first period but lacked a killer ball in the final third and were too often reduced to optimistic efforts from distance.
The hosts still looked toothless after emerging from the break and Porto's greater threat eventually told on 55 minutes when Danilo picked out Gonzalez and his low shot from the edge of the area flashed beyond Lindner.
Goaded into life, Vienna almost got level within two minutes with their first clear-cut chance but Stankovic's header from Fabian Koch's free-kick came back off a post.
With an hour gone Philipp Hosiner also went close for the hosts when he unleashed a shot from 18 yards but Helton made a good save. That brief flurry marked the high point of Vienna's attacking threat, and Porto had little trouble seeing out the remaining half hour.