Real Madrid wore black shirts and black shorts, a novelty choice for a fixture whose aura has been built for more than a century around the fame and lustre of their all-white strip. It meant that Barcelona were also in a form of clasico disguise, dressed in their ‘second’ outfit of yellow with red diagonal stripes. After an astonishing night at the Santiago Bernabeu, the attire helped write the headlines. A dark night indeed for Madrid, 4-0 losers at home to their greatest rivals, a Barcelona who had lost the five previous clasicos, who trailed Madrid by 15 points in the Spanish table going into this, a match that will be remembered as a landmark in what looks like a Barca revival. It may also act as a warning to Sunday’s stunned hosts not to mess with traditional kit, even if the marketing department deems it a good idea. “We could have scored more goals, and I hadn’t expected to be that much better than Madrid,” said Barcelona’s head coach Xavi. So utterly were Spain’s champions-elect – Madrid have a nine-point lead over second-placed Sevilla in La Liga – rolled over by the old enemy that there was genuine frustration on Xavi’s bench that all-time records for winning scorelines in an away victory in the clasico were not being challenged. Pierre-Emerick Aubameyang scored twice. He might have doubled that tally had he not offered a tame save to Thibaut Courtois, busy and brilliant in the Madrid goal, in the first half or miscued his connection with Jordi’s Alba’s cross in the second. Ferran Torres, like Aubameyang a January signing, struck a handsome goal, from a similar spot where he had just squandered a better-set chance to score. Ousmane Dembele ended up in a tangle in a one on one with Courtois, who later added to his catalogue of smart saves to keep out substitute Memphis Depay. After the final whistle the misses had been forgiven. “We are grinning from ear to ear,” said Xavi. Aubameyang could hear his name being sung by the small pocket of away supporters in a high corner of the stadium. Those fans would have to scroll back more than decade to recall as an exhilarating a night as Sunday’s in this most resonant venue. Perhaps to the fabled 6-2 victory in 2009, during Pep Guardiola’s first season as Barcelona head coach. Xavi, then in Barcelona’s midfield, set up four of the goals that evening and, though he is still less than five months into his first senior managerial job in Europe, never has he more resembled the Guardiola-to-be that he is so often styled as a coach. He has clarity in his ideas, and evidently communicates them effectively enough that newcomers, signed from a different league – the Premier League in the case of Torres and Aubameyang – can integrate quickly in into the Xavi plan. Aubameyang, who was still under contract at Arsenal until very late in the winter transfer window, scored his eighth and ninth Barcelona goals against Madrid. He’s only started eight matches. Torres scored for the sixth time since joining from Manchester City. He has five assists, too, and is interpreting his role on the left of a front three with skill and confidence. Dembele, who the club’s executives pushed, aggressively, to leave in January to ease the club’s salary burden, can thank Xavi for making him feel he still belongs. Dembele’s crosses, one from a zippy run, the other from a corner, set up both first-half goals at the Bernabeu, and by the time Adama Traore, another winter recruit, came on as a menacing second-half substitute, Madrid’s back four had been run ragged. “It’s my fault,” said Madrid coach Carlo Ancelotti, admitting that, dynamic though Barcelona were, their hosts were a mess. Missing the injured Karim Benzema, Ancelotti had started the match with Luka Modric as the most advanced player in the centre of the pitch. By half-time he had taken off one full-back, Dani Carvajal, and moved the other Nacho into a back three, so tortured had they been by Torres and Dembele. “My planning was wrong,” admitted Ancelotti. “I can get things wrong once, but usually it’s a while before it happens a second time.” Madrid certainly want to regard the four-goal fiesta as a one-off. What Ancelotti will recognise is that there is a revival under way with their oldest enemies, and that, if the 12-point gap between the clubs in the domestic table won’t be eroded completely this season, it will be very surprising if it stretches so wide in the next campaign.