Real Madrid scored twice against Deportivo La Coruña on Saturday evening, but the loudest noise heard at the Santiago Bernabéu was not the cheers that greeted the goals, scored by Isco and Karim Benzema. It was the whistles of reprobation that accompanied the club's captain, Iker Casillas, when his name was read out before the game. According to the Spanish sports daily Marca, which had arrived equipped with a decibel meter, the whistles measured 110 decibels.

A 2-0 victory – in which the goalkeeper made two important saves – meant that Madrid remained a point clear at the top of the table and that Casillas equalled Raúl as the player with the most league wins in Real Madrid's entire history, but it did not matter, and nor was he alone. They may have been more timid, but there were whistles, too, for Ballon d'Or winner and top scorer Cristiano Ronaldo and for the coach who finally brought them their 10th European Cup, Carlo Ancelotti.

Madrid’s fans are as quick to whistle as they are to applaud. The frustration is often fleeting and swiftly forgotten; a player can be whistled one week and cheered the next, no apology offered or expected. But this was not meaningless, not least because it revealed faultlines among the fans and – in the case of Casillas – a deeper divide that feels impossible to bridge now.

Beyond Casillas, these are difficult days for Madrid. Saturday was Valentine’s Day, “a day to make the fans fall in love again”, a headline had said. It was a week after Madrid had been hammered 4-0 in the city derby, a week, too, since Ronaldo had celebrated his 30th birthday party and some had taken offence, while others flew into the kind of righteous indignation that appears put on. It did not matter that the pictures from the party were extremely tame; just holding a birthday party after such a painful defeat was treated as an insult to fans.

Singer

Kevin Roldan

, the Colombian singer invited to perform, became famous, which may well have been the way he wanted it – after all, they were his pictures that appeared in the press. And the reaction was as overblown as it was manipulated. With no midweek game for the club, it festered too – six days that were a case study in politics and propaganda.

Had Madrid won the derby, the fans may not have cared, but Madrid had been hammered. Amid all the talk about the party, comparatively little was said of the partido, the match, in which they were awful, with just one shot on target all game. Ancelotti had admitted that "Atlético were better than us in everything" and that none of his players had played well. Conceding four was a humiliation; going six consecutive games against Atlético without winning hurt.

So it was that Saturday was billed as the chance to enamour the fans once more, to make it up to them. But the flowers Madrid brought had come from the local petrol station and they were wilting. A flat 2-0 victory did not impress much. Cheers did not replace whistles. “In terms of play, we were the better team,” said Víctor Fernández, the Deportivo manager. That was an exaggeration, but the underlying trend did not feel like it had been reversed.

Concerning trend

That trend is a concerning one. Madrid won 22 consecutive games before Christmas, culminating in the Club World Cup victory against San Lorenzo. Since Christmas, they have lost three and won six. This may not sound too bad, and they are still top, but they are out of the Copa del Rey and the gap in La Liga has closed to a single point.

Of those six wins, perhaps only the victory over Real Sociedad truly impressed. Madrid were fortunate to beat Córdoba with a late penalty from Gareth Bale, they struggled to defeat Sevilla 2-1, and the performance against Deportivo was nothing special.

Injuries do not help. Pepe, Sergio Ramos and James Rodríguez have missed games. So has Luka Modric, whose absence due to a long-term achilles tear, is only now being fully felt, even though the decline in play was soon apparent. There is less fluidity, less creativity, than there was. There is less life, too; they look like a demotivated team, and a tired one.

Ronaldo has dipped in form and is suffering from the inevitable comparisons: from being 12 league goals ahead of Leo Messi two months ago, his lead is now just two. A post-Ballon d'Or drop-off is habitual for the player, but this feels more profound. He has not scored in four games, missed two more through suspension, and has just three goals in 2015.

Ronaldo looks sluggish and disconnected, not entirely fit, while the club has briefed – perhaps self-interestedly – that he is not emotionally right after splitting from his girlfriend. Against Córdoba he was sent off for kicking out at an opponent. Against Deportivo, Isco scored while Ronaldo was still lamenting the chance that had just escaped him and, at full time, he headed down the tunnel without looking back, without winning over the fans.

There is still time. Ancelotti called the return to Europe an “opportunity” back in September, when Madrid had lost two games running, sat in 13th and were six points behind Barcelona. They won that night and then 21 more in a row.

This return to Europe is an opportunity too. The European Cup is a trophy Madrid consider their own, and they are the defending champions; there is motivation where domestically there is monotony. There are good memories too: the last time Madrid went to Schalke, a year ago, they scored six. Guardian Service