Barcelona's hopes of winning the Copa del Rey were left hanging by a thread after Sevilla won the first leg of their semi-final 2-0. Jules Kounde furthered his growing reputation as one of the world's most exciting central defenders by scoring a stunning goal at the Ramon Sanchez Pizjuan before Ivan Rakitic came back to haunt his former club by adding a second late on. The 22-year-old Kounde dribbled past three Barca defenders and shot into the corner while Rakitic's strike turned a setback for Ronald Koeman's side into what now looks like a formidable challenge to make the final. The winner will meet either Athletic Bilbao or Levante, who play the first leg of their semi on Thursday, in the final. "The result is a bit unfair, the reward feels too much for them," said Koeman. "The return will be complicated at 2-0 but we have had chances and we have to keep going. At home, this team is capable of anything." Koeman had described the cup as Barcelona's "shortest route" to a trophy this term and the sight of Kounde ghosting through his defence hardly inspires confidence ahead of next week's Champions League meeting with Paris Saint-Germain. Yet all is not lost in the cup. Although Koeman fielded his best available XI, after resting players against Real Betis in La Liga last weekend, he will also hope to have injured defenders available again for the return game at Camp Nou on March 3. With Ronald Araujo and Gerard Pique out, Koeman played a patched-up back four of Jordi Alba at left-back, the left-footed Junior Firpo at right-back, right-back Oscar Mingueza at centre-back, alongside Samuel Umtiti, who is still regaining sharpness after a string of injuries. "We are halfway through the tie with the hardest half to come," said Sevilla coach Julen Lopetegui. Lionel Messi was quiet but forced a decent save from Bono early on after a superb pass by Antoine Griezmann, with Sevilla the better side in the first half and deserving their goal. Kounde carried the ball out from deep in his own half and bounced the ball off Suso before advancing into Barcelona's defensive third. He ghosted past Griezmann, darted inside Sergio Busquets and with Alba dragged left, nicked it around the legs of Umtiti before driving into the far corner to complete a stunning individual effort. Barca had Marc-Andre ter Stegen to thank for denying Sergio Escudero a second but neither side looked keen to risk conceding by pushing too hard for a goal after half-time. Yet Sevilla were gifted one with five minutes left as Oliver Torres' ball over the top freed Rakitic, who had options inside. Rakitic went alone, blasting into the roof of the net and refusing to celebrate, but putting Sevilla in sight of the final.