Barcelona manager Ernesto Valverde has warned his side against complacency ahead of the deciding leg of their last-16 Copa del Rey tie against Celta Vigo.

Valverde’s team head into the second leg at the Nou Camp on level terms with their opponents following last week’s 1-1 draw at the Estadio Municipal de Balaidos.

Barcelona youngster Jose Arnaiz scored the opener – with Valverde fielding a weakened side – before Pione Sisto ensured Celta gave themselves a fighting chance to progress to the quarter-finals.

The visiting team will be full of confidence after drawing 2-2 with Barcelona’s rivals Real Madrid on Sunday and Valverde, who is likely to call upon Lionel Messi and Luis Suarez for the second leg, insists progression to the last eight must not be taken for granted.

“We can’t think that the result is in our favour because then there is the risk we will make a mistake,” Valverde said. “We won’t think like that. We want to win from the very first minute.

“The tie is slightly tilted in our favour because of the away goal but the advantage is minimal. We are going to try and win the game as if it was a league match, and that is how we have to approach it.

“We want to try and create chances because it is all or nothing as only one team will go through. It is a tie we have to win and it will be a good game to watch.”

Barcelona, nine points clear at the summit of La Liga, completed the finishing touches on Philippe Coutinho‘s British-record transfer from Liverpool, which could be worth up to £142million, on Sunday evening.

The 25-year-old Brazil international was paraded at the Nou Camp 24 hours later, but his debut will be delayed by three weeks due to a thigh injury.

Commenting on his arrival at the Catalan club, Valverde added: “He’s a great signing because he can adapt really well to the team’s style of play, he can play out wide or in the middle and he can score goals as well as creating them.

“We hope he will help us a lot and we are excited about his arrival. I am sure he will bring something different to the team.”

The likely presence of Messi in the line-up will not shift Celta’s tactical approach.

Coach Juan Carlos Unzue, a former Barca assistant boss under Luis Enrique, told Marca: “I don’t feel like employing man-marking on him for 90 minutes, even though some coaches have tried it.

“In a given moment you could mark Messi to make him uncomfortable, but what do we do with the rest of them? With [Andres] Iniesta, Luis Suarez, [Ousmane] Dembele and others?

“That’s why I think more about teamwork.”