On Wednesday, Ronald Koeman's side will seek to overturn the same deficit in the second leg of their Copa del Rey semi-final against the Andalusian club.
The chastening 4-1 Champions League loss to Paris Saint-Germain, where Pique's return from three months out with a knee injury was entirely ruined by him having to try to mark Kylian Mbappe, left Barca's hopes of averting a second trophy-less season hanging by a thread.
But goals from Ousmane Dembele and Lionel Messi made it back-to-back LaLiga wins last time out, while there is the prospect of one or both of the Madrid clubs dropping points when they meet on Sunday.
"We've seen much worse things and the team, despite those two games, is one to believe in this year," Pique said.
"It's not an ideal situation, but I'm confident in the team. Everything is in our head. If we turn it around on Wednesday, the season changes completely."
Wind the pre-match build-up forward a few days and Barcelona's offices have been raided, their ex-president has been arrested, candidates for this weekend's presidential election are lambasting one another in public and Koeman is fielding questions about his future.
It's not an ideal situation.
Of course, this is the state of perma-chaos in which Barcelona resides nowadays. It is a state that persuaded Messi to try to force his exit from the club and it is a state within which they must now convince him to remain when the great man's contract expires in June.
Even more so than in the trophy-laden days that have dominated his record-breaking career, everything at Barca is shot through an unblinking Messi lens.
Take the dramatic off-field developments of recent days.
Josep Maria Bartomeu was the president who drove Messi to the brink of leaving. In fact, the superstar forward was only forced to stay because he claimed Bartomeu went back on a promise to let him walk away if he chose to do so at the end of 2019-20 – a season that, of course, concluded with that implausible 8-2 humiliation against Bayern Munich in the Champions League.
Bartomeu's arrest by Catalan police to face charges of unfair administration and corruption of business was reportedly related to the "Barcagate" scandal, when social media company 13 Ventures were allegedly paid to smear club greats, including Messi. Pricewaterhouse Coopers were commissioned by Bartomeu to investigate the matter and found in Barca's favour.
Joan Laporta, president during those glory years when Messi blossomed under Guardiola, is favorite to be elected for a return to the top job. On Tuesday, he debated opponents Victor Font and Toni Freixa, and Messi was obviously on the agenda.
Laporta believes he is the only candidate who can "ensure" a Messi stay, boasting of "a great relationship with Leo" and using this as a point of difference between himself and Bartomeu ally Freixa.
Font believes he has the best proposition for Messi, namely bring back his old team-mate as head coach. Which is a lovely idea, if not a lovely subject for Koeman to address a couple of hours later at his news conference to preview a potentially season-defining game.
Maybe this is why Messi continues to hold his cards close to his chest. So long as only he knows his intentions over his future, he is in control. Soon enough it will become a matter of public debate, blame, recriminations and conspiracy.
The other thing he still controls masterfully is events on the field.
Much of the talk around Messi's future increasingly centers on his age. Next season he'll be 34. Would he enhance the destructive power of the PSG forward line that wrought such havoc at Camp Nou? Do City need another twinkle-toed creator sauntering in off the right flank?
To dismiss Messi as being over-the-hill, as some would have you believe, needs a little evidence to back it up. He has been most unhelpful in that regard.
In 2021, no player in Europe's top five leagues has more than his 14 goals (level with Robert Lewandowski) across all competitions.
Messi rounded off an all-action showing against Sevilla on Saturday with his 30th goal against them in LaLiga. He has never scored more often against a single opponent.
He supplied the assist for Dembele and completed 41 of 45 passes in the opposition half (91.1 percent). Additionally, the Argentina international has attempted 100 dribbles this season – putting him second to Adama Traore in the top five leagues.
"What he wants is to win again," Laporta said, before casting himself ambitiously at the heart of this story. "If I don't win, I'm sure Leo won't continue at Barca."
It is hard to imagine Messi pouring over Sunday's election results with any great concern. He feels like a man on a mission and in the mood as events clatter on ominously all around him. On the pitch he remains in charge, about the only guarantee an embattled Barcelona have left.