Eintracht Frankfurt continued their fairy-tale UEFA Europa League campaign, coming from two goals down at FC Porto's Estádio do Dragão in a thrilling match between two former winners of the trophy.
Paulo Fonseca's team held the upper hand with goals either side of the interval from Ricardo Quaresma and Silvestre Varela, before Die Adler hit back via Joselu and an Alex Sandro own goal to set up a mouthwatering round of 32 second leg at Frankfurt Stadion next week.
After failing to win a group stage home game for the first time in their UEFA Champions League history this season, Porto looked eager to make amends. On the quarter-hour, Kevin Trapp had to block Hector Herrera's back-post header and the impressive goalkeeper then denied Jackson Martínez. It was third time lucky for Quaresma on the brink of half-time, though, as the winger curled a magnificent effort around Trapp and in off the right post.
Eintracht reacted well at the beginning of the second period. Joselu tested Helton's reflexes, but his firm header from Bastian Oczipka's free-kick was well smothered by the Porto goalkeeper and captain.
Jackson missed a pair of chances as Porto regained the initiative, before Varela got the second, firing into an empty net after Maicon intelligently redirected Quaresma's set piece back across the face of goal.
Eintracht appeared vanquished yet fought back quickly, with Joselu smashing in an excellent low finish from the edge of the area after Porto failed to clear a cross. The away fans were soon in ecstasy as Armin Veh's men levelled. Helton parried to prevent an Eliaquim Mangala own goal but Alex Sandro, attempting to clear, crashed the ball off the underside of the crossbar and into his own net.