Xavi is hopeful that a win over Real Madrid in the semi-finals of the Spanish Super Cup could kick-start Barcelona’s season.
Barca’s form has improved slightly since Xavi’s appointment as head coach in November but they have still struggled for consistency.
Following a 1-1 draw against Granada at the weekend they are one point outside the top four and 17 points behind runaway leaders Real Madrid.
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Barca face Real in the semi-finals of the Super Cup in Saudi Arabia on Wednesday evening, with the winners meeting Atletico Madrid or Athletic Bilbao in Riyadh in the final on Sunday.
"This game is a huge opportunity to reach a final and it could be a turning point for us," said Xavi.
"Madrid are the most in-form side in Spain, the league table shows that, but this is another competition. The Clasico is always unpredictable.
“Getting into a final and then winning a title would give tremendous credibility to our project.
"But whatever happens, we will be realistic. It's an important game and a huge test, one which will show us where we are after [two months in charge]."
Ansu Fati is set to be available for the first time since November while Pedri could also feature and new signing Ferran Torres is in line for his debut.
"It's great news for us that they're all available again," said Xavi. "They're players that are key to the system and can make a difference in the final third.
"As well as Ronald [Araujo] and Frenkie [de Jong], they're coming back from various injuries and Covid-19, so we will manage their minutes, but they improve the team without any doubt."
Real Madrid start as strong favourites having lost just twice in the league this season and beaten Barca 2-1 at Camp Nou in October.
"I've experienced Clasico games when Barcelona have been huge favourites but then lost and vice versa,” said Xavi.
"We're a team in construction but we're trying to do things right. Madrid are in good form but it means nothing. We will try to be ourselves and impose ourselves on the game."
Real head coach Carlo Ancelotti says he is expecting an “even” game.
"I'd be worried if the players though we are favourites, but they don't," said Ancelotti.
"They think we have to give it everything to win. These games are always even, no matter the distance in La Liga. Just like the game in La Liga was."
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