Danilo scored a late penalty as Porto claimed a 1-1 draw with Basel in the first leg of their Champions League last-16 tie this evening.
Basel made the breakthrough in just the 11th minute when Fabian Frei played an inviting pass into the path of Derlis Gonzalez, who timed his run to perfection to slot past a helpless Fabiano.
Despite making an impressive start, Basel would be forced onto the back foot for much of the game, and they lost Gonzalez to an injury he picked up in the process of opening the scoring.
Porto dominated for long spells, and Tomas Vaclik was required to keep Basel ahead with saves from a Casemiro header and a low strike from Danilo.
The visitors continued to threaten from both open play and set pieces, with the latter creating another chance for Casemiro, who headed wide after finding space at the front post.
There was controversy early in the second half when Porto thought they had equalised through Casemiro, who fired home after Vaclik had saved Maicon's header.
However, Mark Clattenburg discussed the incident with his fellow officials and decided to disallow the goal when his assistant informed him that two Porto players were standing in an offside position as Casemiro converted.
A long ball over the top caused problems for the Basel defence as Cristian Tello's touch earned him space, but he could only fire his effort straight at Vaclik from a tight angle.
Jackson Martinez was kept quiet by the Basel defence for much of the match, and he wasted his best chance to find the back of the net when he chipped over the crossbar after shrugging off a couple of challenges.
Porto were finally rewarded for their dominance late on when Walter Samuel conceded a penalty for handling the cross to allow Danilo to fire home the potentially crucial away goal.