After it appeared the Catalan giants would miss out on the Liga title, they've been handed a lifeline which Xavi says they must take advantage of.
Barcelona must seize its "historic opportunity" to win La Liga on Saturday, according to midfielder Xavi.
The Catalan giants looked like they were out of the title race after a 2-2 draw with Getafe earlier this month, but both Atletico and Real Madrid's respective failures to win gave them another chance.
Real's defeat to Celta Vigo last weekend saw the club fall out of contention, meaning the title will be decided in Barca's game with Atletico at Camp Nou this weekend.
Gerardo Martino's men must win to claim top spot, while Atletico can draw and secure a first league title since 1996.
Xavi admits he thought the chance had gone but says Barca must now take the chance given back to it by winning the title decider in front of their own fans.
"We thought it was bleak, we thought we had lost La Liga but football has given us another opportunity," the midfielder said Wednesday. "We are playing at home in front of our fans and we have everything in our favor to win. We have a historic opportunity.
"It will be a spectacular final. Anyone who thought we would still have a chance would have been classed as crazy! All we want to do is win the league. This is a unique match and I do not know if we will ever experience something like this again."