Barcelona missed Gerard Pique against Malaga on Saturday. The centre-back was suspended after picking up too many yellow cards and could not play. And Luis Enrique's team suffered in his absence. Really suffered.
In the end the Blaugrana squeezed their way to a 2-1 win at La Rosaleda, but on another day they could easily have left with nothing. In the first half particularly, they were under the cosh, with the Andalusians dominant.
Barcelona improved in the second period but still were fragile and a lot of that is down to Pique's absence.
Not all of it, though. There were, of course, plenty of other factors that negatively impacted on the Catalans.
They faced Athletic Club in Bilbao on Wednesday night in the Copa del Rey quarter-final first leg, which was a draining, bruising encounter. Barcelona were visibly upset with the aggression aimed at them from the Basque side, and it's no surprise they weren't at the top of their game.
Apart from Pique, they were also lacking other key players. Neymar, for one, the third best player in the world, according to FIFA's Ballon d'Or ceremony.
Without the Brazilian in the side, with Munir El Haddadi in his place, it allows opposition to concentrate less on defending and attack themselves. Perhaps in Malaga's case too much, because Munir scored after just one minute.
Furthermore, Jordi Alba and Dani Alves were also not playing, the former because of injury and the latter was rested, bearing in mind Barcelona have to play Athletic again in mid-week and then title rivals Atletico Madrid next weekend.
That meant, with Pique suspended too, three-quarters of the usual defence was out, with only Javier Mascherano holding the fort, alongside Adriano, Aleix Vidal and Thomas Vermaelen.
Malaga, meanwhile, have been on a run of good form, and when players like Andres Iniesta and Sergio Busquets have off days too, things are always going to be tough.
But, despite all these other factors, which had some influence, Barcelona were clearly weaker without Pique at the back.
OPTA statistics show that Claudio Bravo made more saves in a single game than since he joined Barcelona, with eight against Malaga.
It shows the defense was more permissive than usual, with Vermaelen, the man who came in for Pique, making some striking errors.
Until this point, Vermaelen had enjoyed a good season, impressing whenever selected to fill a gap. But this was a horror show.
The worst mistake came when he fell over while trying to stop Malaga striker Charles, with only an excellent covering tackle by Mascherano saving Barcelona at the time.
Juanpi equalised after half an hour, with the whole defence at fault. Busquets passed the ball to Mascherano in a tricky spot, and he gave it away.
Vermaelen looked lost and bewildered as Malaga constructed a quick attack, and before he and Barcelona knew it, the ball was in the net.
The team lacked purpose and leadership, both of which Pique delivers. The defender still makes mistakes; he is far from flawless. But he makes up for them with towering performances, and the ability to inspire his team-mates.
Sport's Albert Masnou detailed in December how he became a leader at the back, after previously being the player Carles Puyol had to occasionally reprimand for not paying attention. He wrote:
Pique is more mature than ever, taking a step forward to become the best centre-back in the world. He is a key part of Luis Enrique's team, like Busquets, Iniesta and Messi, he represents an understanding of the play, the spine of the team, the start of moves. His performances this season are becoming spectacular. More than ever, he is combining security, seriousness and leadership.
Those are precisely what Barcelona lacked against Malaga.
Luis Enrique hooked Vermaelen at half-time, putting on Jeremy Mathieu. The Frenchman is not without his flaws, but he has a cool head and helped stabilise Barcelona for the second half.
We saw Pique play badly against Celta Vigo earlier this season, but since that game he has been a mountain at the back for Barcelona and a performance like this is hard to envisage happening on his watch.
Of course, Barcelona's victory meant this game can and will be forgotten about, but one thing remains very clear: Pique is a totally essential, non-negotiable part of this Barcelona side. Not only is he part of the spine, he is the start of it.
Most people at Barcelona could send those words right back at Pique, because plenty of things start with him, and that was clear as day against Malaga.