Eintracht Frankfurt beat Barcelona at Camp Nou to end the hosts’ dream of winning a European trophy this season.
With the tie equally poised after the first leg in Germany, the visitors turned on the style in Spain to outclass Barcelona 3-2 on the night and 4-3 on aggregate.
Roared on by massive travelling support of 30,000 fans, the visitors took the lead in the 4th minute of the game.
Barca’s Eric Garcia hauled down Jesper Lindstrom in the area, his second penalty give away in as many games, and Kostic calmly beat Marc-Andre ter Stegen from the spot to give Frankfurt an early lead.
Xavi Hernandez’s side settled quickly after conceding and began to force the issue, with Ousmane Dembele setting up Pierre-Emerick Aubameyang whose header went over the crossbar before Ronald Araujo volleyed straight at Kevin Trapp in the following minutes as the home team looked for an equalizer.
Frankfurt, though, did not have to wait till the second-half to add to the score line.
Rafael Borre’s absolute thunderbolt of a shot from distance blistered past Ter Stegen to hand visitors a two goal cushion.
With Barcelona trailing 2-0, the match was wide open from the start of the second half.
Aubameyang forced a point-blank save from Trapp in the 48th minute before Ter Stegen had to do well to keep out a powerful Lindstrom shot at the other end soon after.
Xavi brought on Adama Traore for Aubameyang just past the hour mark and substituted Sergino Dest in place of Oscar Mingueza in hopes of jumpstarting the attack.
But Kostic scored his second of the night with a low drive past Ter Stegen in the 67th minute to practically guarantee a win for Frankfurt.
Barcelona, at least, made a game of it in the closing stages.
Sergio Busquets scored Barca’s first as the second-half stoppage time began before Memphis Depay added one from the spot just before the final whistle.
Despite the nervy moments in the end Frankfurt beat Barcelona for one of their most famous wins in history.