When it came to offering an explanation, José Mourinho favoured fortune but he did not convince. Fifteen successive victories came to an end with Real Madrid defeated 3-1 by FC Barcelona at the Santiago Bernabéu, despite scoring the fastest goal in a Clásico. Twenty-three seconds were all it took for Karim Benzema to give them the lead; by the full‑time whistle, though, that felt like a distant memory. Alexis Sánchez, Xavi and Cesc Fábregas sent Barcelona back to the top of the table on the night that Madrid had prepared to tilt the balance of power in Spain.

"The result," said the Madrid coach, "was a consequence of football. It's a game and luck plays a big part." Mourinho noted that Leo Messi might have been sent off for a second yellow card, but this was not the normal conspiratorial discourse: "I was 40 or 50 metres away from it so I don't want to say it was the wrong decision because that might be unfair," he noted. Instead, he focused on the moments that could have gone his side's way; the chances Madrid missed and the goals Barcelona scored.

At 1-0 Cristiano Ronaldo scuffed a clear opportunity and he also missed a simple header. Kaka's late shot skidded wide off Víctor Valdés. Then there was Barcelona's second goal – Xavi's deflected shot squirmed in via the post as Iker Casillas scrambled back across goal. "That was pure luck," Mourinho said. "It was not talent, it was not a mistake, nothing – it was just lucky. At 1-0 we had a chance to make it 2-0 and Cristiano, who's a fantastic player, normally scores those. Then Kaka's shot went wide off Valdés, which was lucky, too."

Perhaps. But there was also an inescapable reality here: Barcelona were simply superior. Were? Are. Madrid's winning run was no guarantee; the perception that they were closing on their rivals was undermined. There is only one team against which they are truly measured – and that is FC Barcelona. On the evidence of Saturday night, they are not in quite such rude health after all. The good news is Madrid only face them twice a season in the league; it is true, as Mourinho noted, that they will return to the top if they win their game in hand, and they may remain favourites for the title. But still this hurt.

Not least because of the familiarity. This was no one‑off. Mourinho claimed that if he could choose to have won one Clásico as Madrid manager, it would not be this game, or the Spanish Super Cup clashes, or the Champions League semi-final, but the Copa del Rey final – conveniently the one he did win. He reasoned that there was a title at stake that night. But the Copa del Rey is the least important trophy and the statistics make for concerning reading.

Mourinho's first match against Barcelona ended 5-0, his worst defeat as a coach. Although he insisted that the figures did not tell the whole story – "you have to see how those results came about" – as Madrid manager he has faced Barcelona eight times in18 months across four competitions and won just once, losing four times. Of the three draws, two occurred when Barcelona knew that drawing was sufficient for their interests. The aggregate score reads: Barcelona 17, Real Madrid 8.

Every game against Barcelona is not just important in its own right but as part of a learning process – a search for the solution, a plan. Mourinho has tried a number of approaches with different personnel and different formations. On Saturday, he bemoaned his side's passivity; they have tried ultra-aggressive before. They have been defensive and attacking, played high up and sat deep. Only once has it worked – and even then, although they probably deserved the victory, they scored an extra‑time winner and had Casillas to thank for rescuing them. The very next game, Mourinho employed entirely different tactics.

This time, Madrid appeared secure: bold and aggressive, quicker and more decisive, than ever before. Mourinho's teams are better in the second season was the mantra, repeated over and over. It was true, too. But Barcelona are another proposition altogether, a team that make very good sides look very ordinary. A formula that is valid against Valencia may not work against Barcelona. Mourinho has not yet found the definitive way. This was a better Madrid and a Barcelona assailed by doubts. But again Madrid, despite the perfect start, were defeated.

With each passing game, the trauma grows; there is a psychological element to it now, a sense of anxiety. Again, the question is raised: how should Madrid approach their rivals? How do they stop Messi? How do they wrest control? Is it best to assimilate their inferiority and play defensively, despite a starting XI that cost more than €300m, despite the talent they have? In Spain, that question has transcended the tactical, becoming almost a moral issue. There are many questions. The search for a successful identity continues.

Barça's coach, Pep Guardiola, praised his side because even when they trailed, even when they doubted, they remained faithful to their philosophy, their identity. They have one. When it comes to the Clásico, Madrid still do not. Maybe that is the greatest difference of all.