Hansi Flick used an expletive to describe Barcelona's poor performance during November, and December was equally bad, with Atletico Madrid's win before Christmas helping them usurp the Catalans at the top of the table.
However since Barcelona lost at home against the Rojiblancos they have gone on a 17-game unbeaten run across all competitions, winning 14 of those matches and drawing three.
In LaLiga they have reclaimed pole position, above Real Madrid on goal difference and Atletico, third, by one point, despite having played one fewer game than the capital clubs, ahead of their clash against Diego Simeone's side on Sunday.
After a strong start to the campaign, their winter tail-off suggested Flick's side were heading for disaster but a superb start to 2025 has changed the picture completely.
A good result at the Metropolitano stadium would complete a superb week for the Catalans, after they reached the Champions League quarterfinals with a comfortable 4-1 aggregate win over Benfica.
"No one cares about what happened in the past when you lose a match, so it's a really good thing to always focus on the next match, and bring everything that you can give for the team, for success," said Flick after Barca beat Benfica.
"I love this mentality, and they are really focused.
"I also think they have a lot of fun together, and at the moment it's a great atmosphere, and it helps a lot to get the success we want to have."
SIGHTS ON TREBLE
There are various factors which have aided Barca's revival, as the team sets their sights on a potential treble – they face Atletico again in the Copa del Rey semifinals.
Flick has made two major changes to his side, with goalkeeper Wojciech Szczesny and midfielder Frenkie de Jong establishing themselves as first-choice in their respective positions.
Inaki Pena and Marc Casado have dropped out and Barcelona look both more solid at the back and more threatening in attack.
Szczesny has eight clean sheets in 15 appearances, while De Jong looks to have regained his confidence after a long spell of inconsistency.
The winter break helped Barcelona to take a physical and mental reset, and combined with the work of the fitness team, they are benefitting from that freshness now.
"The physical job I don't do, this is the fitness side, Julio (Tous) and his team," said Flick.
"They make a fantastic job. Deco (the sporting director) made a good job when he planned all the new experts to come in and help us. You can see this."
While other sides including Real Madrid are suffering with various injury problems, with the exception of long-term absentees Marc-Andre ter Stegen and Marc Bernal, as well as defender Andreas Christensen, Barcelona have a clean bill of health.
That is also in part due to Flick's increased faith in his squad, rather than just a starting line-up.
Ronald Araujo and Eric Garcia are not in the coach's best side but get regular minutes, along with Fermin Lopez, Ferran Torres and Gavi.
"To win the league we need a lot of players, not just 11 or 12, but a good bench too, the coach is managing that very well," said Araujo.
"Everyone comes on with confidence, they are happy and they know they can help the team."
Flick will be happy with the way his side managed the game in the second half against Benfica, protecting their advantage.
Against Atletico in December Barcelona conceded a 96th minute goal to lose 2-1, and when facing Simeone's side in the cup semifinal first leg, conceded two late goals to draw 4-4.
Barcelona will get a third bite of the cherry on Sunday with the chance to strike a huge blow in the title race and show just how much they have improved since they last tasted defeat.
Player to watch: Ayoze Perez
When fit Villarreal striker Ayoze Perez has pulled up trees this season. The 31-year-old forward has 11 goals in 19 league appearances and poses a threat to champions Real Madrid on Saturday, with the Yellow Submarine still fighting for Champions League qualification and looking to bounce back from a shock defeat by Alaves last weekend.