Basel have taken a 1-0 lead into the break against Porto thanks to Derlis Gonzalez's early goal in the first leg of the Champions League last-16 tie.
It was the perfect start for the hosts as they broke the deadlock with their first chance of the match when Fabian Frei played an inch-perfect pass to find the run of Gonzalez, who kept his composure to slot home.
Gonzalez collided with Porto goalkeeper Fabiano in the process of opening the scoring, and the effects would force him to be taken off later in the first half.
Tomas Vaclik was forced into a couple of saves to protect the lead as he held on to a Casemiro header before tipping Danilo's low effort past the post.
Porto's impressive response continued as another set piece created a chance for Casemiro, who somehow managed to send a free header wide of the post.
Despite dominating the match heading into the break, Porto were unable to find an equaliser as Basel's stubborn defence held on to the advantage.
Callum Mulvihill
