Spanish title contenders Girona earned a historic 4-2 win over rivals Barcelona on Sunday to move to the top of La Liga, with coach Michel saying he believes his team can beat any opponent.
Girona defeated their Catalan rivals for the first time ever in the top flight in a pulsating battle to rise two points above Real Madrid, second, after their 1-1 draw at Real Betis on Saturday.
Champions Barcelona are fourth after Atletico Madrid, third, beat Almeria earlier on, and Xavi's side trail Girona by seven points.
Artem Dovbyk sent Girona ahead and after Robert Lewandowski pulled Barcelona level, Miguel Gutierrez slammed home again for the visitors.
Valery Fernandez extended Girona's lead with 10 minutes remaining before Ilkay Gündoğan netted to set up a frantic finale.
Veteran striker Cristhian Stuani struck from close range in stoppage time to wrap up a stunning victory that reaffirmed the minnows' title dream.
"We're enjoying the moment, we're in a hugely positive dynamic," Michel told reporters.
"I don't know if we have the ability to win La Liga, but we are able to beat any opponent."
The defeat leaves Barcelona's title defense badly dented.
"They deserved it, they've got a lot of merit, they're seven points ahead of us," Xavi told DAZN.
"We want to cut down the gap; this is our reality – this is a Barca under construction, although they have criticized me for (saying) it.
"You take one step back to be able to take two steps forward."
Girona, part-owned by the City Football Group, were without injured key midfielder Yangel Herrera, whom they signed from Manchester City, but did not let it set them back.
In La Liga, for only the fourth season in their history, they played without any fear of their more illustrious neighbors and took the lead early on as the game see-sawed deliciously from end to end.
The visitors split the 27-time champions open with a lethal counter-attack, with Ukrainian winger Viktor Tsygankov feeding his compatriot Dovbyk to slam home in the 12th minute.
Unperturbed, Barcelona leveled quickly through Lewandowski, with the 35-year-old heading home Raphinha's corner to end a run of three matches without a goal.
End-to-end
Former Real Madrid left-back Gutierrez, no stranger to an adventure upfield, drove into the box and cracked an early strike into the near top corner five minutes before the break.
Barcelona tried to force their way back in, with Paulo Gazzaniga saving Frenkie de Jong's low effort and Raphinha sending a free-kick over the bar.
Valery seemed to end Barca's hopes with 10 minutes to go when Stuani headed the ball into his path, and he beat Jules Kounde with ease before firing home.
However, Gündoğan turned well in the box and lashed past Gazzaniga to give the hosts a chance to snatch a draw. Lewandowski might have leveled but headed wide when well-placed.
Stuani bundled home at the death to complete a sensational night for Girona, with several players leaping the advertising hoardings and running towards their fans in celebration.
Michel said beforehand that a win would send his team into a new dimension, and there can be little doubt that they are genuine title contenders this season.
Barcelona's title defense, however, is on the ropes.
"We're seven points behind, which is a lot, but there's more than half a season to go," De Jong told DAZN.
"There's time, but we have a lot to come back from."
Earlier, Diego Simeone's Atletico took an early two-goal lead through Alvaro Morata and Angel Correa, but Leo Baptistao pulled Almeria into the game after an hour.
Atletico held on for the victory as the Andalucian strugglers threatened to pull level at the Metropolitano.
"They pressed us in the second half, we couldn't find solutions and it was hard for us," Atletico forward Antoine Griezmann admitted to Movistar.
Athletic Bilbao's visit to Granada was stopped in the 18th minute because a fan died in the stands, and the match was subsequently abandoned.
Inaki Williams had sent the Basques ahead and they will resume play with the lead on Monday night from 17 minutes.