Porto kept alive their hopes of reaching the Champions League knockout phase after Jackson Martinez earned a 1-1 draw against Austria Vienna.
The Colombian finished from close range after Roman Kienast had given the visitors a shock lead in Portugal with their first goal in the tournament.
The result means the Portuguese champions missed the chance to move above Zenit St Petersburg into second in the group but they remain in contention to reach the next round.
Vienna can no longer qualify for the last 16, while Porto must win at Atletico Madrid on matchday six to have a chance of overhauling Zenit and claiming second spot in Group G.
Should Zenit defeat Vienna in their final pool match, Porto will not be able to progress.
Home coach Paulo Fonseca made three changes from Saturday's 1-1 draw against Nacional, with midfield duo Lica and Steven Defour taking the places of Silvestre Varela and Hector Herrera.
Nenad Bjelica unsurprisingly opted to stick with the same Vienna line-up that recorded a 5-0 win over Wacker Innsbruck at the weekend.
The visitors wasted little time in finding the target again as Kienast shocked the home crowd.
The 29-year-old forward picked up a loose ball out of defence with yards of space around him, before keeping his composure to fire neatly past goalkeeper Helton.
Heinz Lindner was soon called into action at the other end, tipping Martinez’s header over the crossbar.
The Austria goalkeeper came under increasing pressure as the half wore on, with Vienna penned further and further back into their own half, but the hosts struggled to find an effective final ball and ended the half behind.
Porto appeared to be well served by the interval and it was not long before Martinez rose high to score after Eliaquim Mangala had nodded back across goal.
The Colombian had a fine chance to notch the winner in the 64th minute, but after getting mixed up with strike partner Varela, who was introduced at half-time, he saw a deflected effort land on the roof of the net.
As full-time approached, the hosts continued to turn the screw but just could not find a way through, with Martinez’s header eight minutes before time also sailing over.
Porto now boast five points from as many group matches and must hope Vienna are able to prevent Zenit from taking maximum points on December 11.