Hansi Flick will not be resting his key players as Barcelona take on Young Boys in the Champions League.

Barcelona's winning start in LaLiga came to a shuddering halt when they slumped to a 4-2 defeat at Osasuna on Saturday.

Flick said after that defeat that he had made too many changes.

And while he hopeful midfielder Frenkie de Jong can return as Barca look to bounce back after suffering two losses in 10 days, following their defeat to Monaco in their first Champions League match, he is still set to be without Dani Olmo, Ronald Araujo, Gavi and goalkeeper Marc-Andre ter Stegen.

"We will play with the team we believe to be the best in order to beat Young Boys. The first game we lost, yes. But we must not be depressed," Flick told reporters.

"We have to recover our balance after the defeat at Osasuna. We have to build the game with fewer mistakes. Responsibilities must be assumed.

"We need fresh legs and Frenkie's return is great news. Even if it's just for five or 10 minutes. If he gets the chance, he'll play."

Young Boys will arrive in Spain following a 3-0 defeat by Aston Villa in their opening Champions League match at home.

Asked if the five-time European champions have lost respect after their defeat at Monaco, Flick said: "I am positive we can win, we play good football - entertaining football. And if we need to gain the respect of our opponents once again, we're going to work hard on that."

Flick added he is in contact with Polish goalkeeper Wojciech Szczesny, who has reportedly agreed to come out of retirement to help Barca following first-choice Ter Stegen's season-ending injury.

He added: "Yes, I spoke with him, but I'm not going to say anything more. If he signs for Barca in the next few days at the next press conference we can talk about the issue, but not now."