Ajax may have been in the midst of winning three successive European Cups in April 1972, but they were not having things all their own way domestically. Indeed, since the extraordinary genius of Johan Cruyff first began wowing the Amsterdam giants’ supporters in 1964, they had only seized four Eredivisie titles to Feyenoord’s three.

The Rotterdammers had, themselves, lifted the continent’s biggest prize in 1970 and were the reigning Dutch champions. They boasted the legendary Ernst Happel in their hot-seat, had arguably their country’s greatest-ever defensive partnership in Rinus Israel and Theo Laseroms, the craft of Wim Jansen in the engine room and a magician supreme of their own in Wim van Hanegem.

“Feyenoord and Ajax were at the time not only among the best sides in the history of Dutch football, but European football,” said Happel later.

Forty years ago to this day, Stefan Kovacs took the team he had recently inherited from Rinus Michels to Rotterdam for one of the Netherlands’ most eagerly anticipated all-time clashes. It was Round 29 of 34 in the Eredivisie run-in, and Ajax had had their lead at the summit cut to just three points after losing their last away game 3-2 at mid-table Go Ahead Eagles. The odds suggested the arch-enemies would be neck-and-neck at the end of play. For Cruyff’s first De Klassieker had ended in a 9-4 humiliation in 1964, and by now they had gone nine attempts without a league win at De Kuip.

“The previous season Ajax had been ahead of us in the title run-in, but we beat them 3-1 in Amsterdam and one week later we were champions,” said Israel. “Now we had home advantage. Ajax didn’t score many against us in Rotterdam and we had a very good record against them. We were very confident we were going to give our fans a day to remember.”

Those Feyenoord supporters were, as Israel had desired, applauding at the end of 90 minutes. However, for the first and only time in their history to date, they were applauding Ajax.

With Piet Keizer and Cruyff dazzling, the visitors were 3-1 up by half-time courtesy of goals from the latter, Arie Haan and Gerrie Muhren. Keizer’s third assist of the contest allowed Cruyff to complete his brace, before the pair reversed roles to put the icing on the most sumptuous of cakes. When Keizer slid home that Cruyff pass to complete a 5-1 victory, the left-lying attacker cockily stood still and stared at the ball, which was in the back of the net along with Israel, who had desperately slid into it in an attempt to restrict the ignominy.

“I remember lying there, half-conscious in the goalmouth, and seeing that celebration," said Israel. "It was hard to take, but Ajax deserved that victory. People criticised our performance, but they were simply unstoppable that day. It wasn’t just Cruyff and Keizer, the whole team played really well. It was an amazing performance.”

That result all but regained Ajax the Eredivisie title, and the following month they were ironically back at De Kuip to beat Den Haag 3-2 in the KNVB Cup final and Internazionale 2-0 in the European Cup decider.

“We had three unforgettable nights in Rotterdam in that summer of 1972,” recalled Keizer, who spent his entire career with Ajax. “But that 5-1, against our biggest rivals on their own patch, was something extra special.”