Pablo Machin's side, though, ended the interest of Athletic Bilbao in the previous round following an impressive 3-1 away first-leg win.

Sevilla are also currently fourth in the table and very much in the shake-up for Champions League qualification.

Valverde knows Barcelona cannot afford to lose focus if they want to stay on course for a potential fifth successive Copa del Rey triumph.

"Our analysis was based on the fact that they are a strong rival at home and in the knock-out ties they have always been very solid," the Barcelona coach said at a press conference.

"Sevilla are a great team with experience in the qualifying rounds and have the measure of this competition. They will be a tough team in this tie."

Barcelona secured a place in the quarter-finals having progressed against Leganes, winning 3-0 at home to overturn the 2-1 away first-leg defeat.

Leganes, though, maintain Blaugrana defender Juan "Chumi" Brandariz played in the fixture despite having been suspended by the Spanish Football Federation (RFEF) after collecting a fifth yellow card while playing in the Segunda Division B.

The club's appeal to the RFEF was rejected on a submission deadline technicality, but Leganes intend for the matter to be heard at the Court of Arbitration for Sport and have called for Barcelona's tie against Sevilla to be postponed.

Valverde said: "We have done what we thought we should do, the law is there and we prepared for the game. It is not in our hands, and I do not have much to say about it."

With Ousmane Dembele sidelined because of a sprained ankle, Philippe Coutinho is expected to be handed another chance in the Barcelona frontline.

Sevilla are set to be missing forward Munir El Haddadi for up to a month with an abductor muscle problem, while French defender Joris Gnagnon is also not fit.

Machin believes his squad must maintain a positive mindset, no
matter what the calibre of opposition.

He said at a press conference: "We must be prepared if we are to beat Barcelona. It's a complicated tie and I'm sure they think the same as us.

"No-one wanted the current leaders of La Liga and the team who has won the past four cups. But, should we go through, it would make it all the more sweet."

The Sevilla boss added: "If we are to cause a surprise in this tie, because we all believe Barca are the favourites, we need to bring a result to the Camp Nou where we don't have to score more than one goal."

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