Xavi believes it will be a "catastrophe" if Barcelona do not beat Girona on Saturday as they look to keep up their LaLiga title charge.
A run of seven wins in eight league matches has put Xavi's men top of the table, holding a three-point lead over rivals Real Madrid in second.
They continue their bid to win their first LaLiga title since the 2018-19 season on Saturday at home to Girona, who sit 11th and just four points above the relegation zone.
Xavi hopes his team can pick up another three points amid the pressure of a title race, telling reporters: "You have to beat Girona. This is Barca.
"This is the Barca environment, I know it very well. If we don't win tomorrow, it will be a catastrophe.
"Try to win it because it will be a difficult match. Michel [Girona head coach] has said that they have nothing to lose and we will come out with pressure because we want to win LaLiga."
Xavi is hoping Ousmane Dembele will extend his Barcelona contract amid rumours of a move to Paris Saint-Germain.
Dembele scored Barca's winner as they beat Real Sociedad in the Copa del Rey quarter-finals on Wednesday, continuing his excellent form this season after a tough 2021-22 campaign.
The France international has been involved in 15 goals with Barcelona in all competitions this season, already equalling his record of last term, but with his contract set to expire in 2024, there had been rumours of a move to PSG.
But Xavi wants Dembele to remain with the Spanish giants, telling reporters: "Ousmane is an important player, someone who makes a difference.
"It's difficult to find these kind of players. For me, he's a key player. Ousmane knows it, the club knows it.
"He has changed his mentality and I hope to have him here for many more years."
Barca overcame wastefulness in front of goal to overcome La Real and reach the Copa del Rey final four, with Dembele's goal enough to secure a narrow 1-0 win despite having 20 shots.
While Xavi is concerned about his side's profligacy in front of goal in tight matches, he believes his team are much improved from last season, saying: "I am worried about not finishing them [close games]. Many things have to be improved
"We have to value how we were last year and how we are now. There are things to improve, obviously, but I think we are in a very good moment of form and it should be valued."