Quique Setien has no concerns about Barcelona failing to sign a striker in the January transfer window because Ousmane Dembele will be "amazing" when he returns from injury.

Barca director Guillermo Amor confirmed before Thursday's 5-0 Copa del Rey last-16 victory over Leganes that no back-up to Luis Suarez – ruled out until May with a knee injury – will be signed, negotiations for Valencia attacker Rodrigo Moreno having broken down.

Lionel Messi scored twice and was involved in the other three goals as Setien's side enjoyed serene progress to the quarter-finals, with Antoine Griezmann, Clement Lenglet and Arthur hitting the target.

Setien acknowledged the lack of a new signing leaves Barca's attack in a precarious position, though Dembele has been eased back into full training since the weekend having been sidelined since November with a thigh injury.

Asked about the lack of a signing, Setien said: "I will be calm. There is a risk of injury and it cannot be controlled. I am used to working with what I have.

"It was not to be. The market did not give us anything, but we will also recover Dembele.

"He is a player who has specific attributes and I think he can give us a lot. He feels comfortable out wide and we will try to take advantage of that.

"I'm sure he will give us a lot with the potential he has and will demonstrate the great player he is. Dembele is going to be amazing."

Dembele signed from Borussia Dortmund for an initial €105million in August 2017 but has frequently struggled with injuries.

Barca's victory over Leganes saw them emphatically bounce back from the first defeat of Setien's tenure, a 2-0 loss to Valencia on Saturday that saw them fall three points behind Real Madrid in LaLiga's title race.

"We did very well in the first 20 to 25 minutes. It's true they could have hurt us, but we did many things well. However, I am not entirely satisfied," Setien said of Thursday's display.

"We scored but we lost control of the game and gave them a lot of life when we had to control the game."