Barcelona coach Ronald Koeman does not believe Sevilla's 2-0 Copa del Rey semi-final first-leg win over the Blaugrana was a fair reflection of the match, while he also questioned the officials.

Jules Kounde opened the scoring in the first half with a fine individual effort, before former Barca midfielder Ivan Rakitic wrapped up a potentially significant win in the latter stages.

Lionel Messi did go close several times for the visitors, with Sevilla goalkeeper Yassine Bounou keeping him at bay as he made four saves in total – the Moroccan has saved all 18 shots on target he has had to face in this season's Copa.

The two teams renew hostilities at Camp Nou on March 3 for the second half, though Barca have only progressed past Sevilla once in the Copa when losing the first leg to the Andalusians.

Barca shaded the possession (53.6 per cent) and their 13 shots were two more than the hosts, with Koeman left convinced his side had been hard done by.

"It is a result with too much reward for them," Koeman said. "We have seen a Barca playing well, creating a very clear chances.

"We have put a lot of pressure in the second half. I cannot blame the team. There is another game left, we have to try to win and play the final.

"It is difficult at 2-0. We had opportunities to score, but their defence was good, as was their goalkeeper too, but at home this Barca is capable of anything."

Barca were left frustrated by a moment in the second half where Suso was adjudged to have fouled Jordi Alba just outside the box, yet Koeman and his players were convinced the offence occurred inside the box.

The VAR did not appear to intervene, and this left Koeman bemused.

"Mateu Lahoz [the referee] I think was good in general," Koeman said.

"Of course, there was always doubt with the incident of the penalty, because everyone says it was a penalty, so I have to believe them – not only the Barca people [said it should have been a penalty].

"I don't know why the VAR has not intervened."

Sevilla go into the second leg with a significant advantage and know that an away goal will give Barca a mountain to climb, but they are not getting ahead of themselves, aware the most difficult task is yet to come.

"We knew it was going to be very difficult, the team played a great game, we fought to the end and that is worth it, football gives back to you in this way," Rakitic said.

"But we have half the work left to do in Barcelona."

Coach Julen Lopetegui echoed that sentiment, adding: "The team played a great game against a Barcelona that arrived in good form.

"We played well, we defended well and it was a very beautiful game. Now, we have the most complicated and most difficult thing left, which is to play at the Camp Nou. We are aware of the challenge."