It was one of the greatest nights in Tottenham’s history. It was better than beating Internazionale 3-1, probably the equal of those fraught nights in 1983-84 when Bayern Munich, Austria Vienna, Hajduk Split and Anderlecht were overcome on the way to the Uefa Cup. Almost whatever happens over the next three decades, it is safe to assume that in 2050 Christian Eriksen’s goal will still be included in the pre-match White Hart Lane montage as Danny Blanchflower’s voice, the crackle of time even more pronounced, explains once again that the game is about glory.

And this was glorious. The European champions were humbled. As Eriksen pointed out, if Spurs had shown a little more composure, they would have had more. If Harry Kane had been fully fit, perhaps, they would have had more. If Spurs had been able to believe quite what was happening, they would have had more. Dele Alli admitted he was astonished by the amount of space Madrid had allowed them.

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That hints at a wider point, which is that Madrid were weirdly terrible. That is not to diminish Tottenham’s performance, and it is hugely to their credit that they have adapted their game this season to such an extent their best three performances – against Borussia Dortmund, Liverpool and Madrid – have come when they had only around a third of possession, but it is to ask questions about Zinedine Zidane and, perhaps, the nature of elite football in general.

Nine years ago the former Liverpool midfielder Igor Biscan spoke about the problem clubs such as Dinamo Zagreb have, explaining how they dominated to such an extent domestically that they wilted as soon as they meet a side of even vaguely comparable quality in Europe. They had forgotten how to defend and they had forgotten how to fight.

Football became for their players an exhibition, the sense that you might have to struggle before you could express yourself was gone.

Since then, the economics of football have meant more and more teams have found themselves succumbing to the Biscan Principle. Bayern are now laughably dominant in the Bundesliga. Juventus may be facing more of a challenge this season than in recent years but they have won Serie A six times in a row. PSG were so upset when their run of four successive French league titles came to an end last season that they went and arranged the two most expensive transfers in history; their only rival, meanwhile, lost four key players. Barcelona and Real Madrid dwarf the rest in Spain.

Quick guide Champions League group stage classics involving English clubs Show Hide Newcastle 3-2 Barcelona (Sep 1997) Described as 'the most spine-tingling, frenzied and, ultimately, nerve-wracking 90 minutes ever witnessed at St James’ Park' Newcastle’s victory came courtesy of Faustino Asprilla’s brilliant hat-trick. Barça gained their revenge at the Camp Nou but both ended up finishing behind Dynamo Kyiv Man Utd 3-3 Barcelona (Nov 1998) Despite throwing away a two-goal lead, it proved enough to take United through ahead of Barça, before going on to win the final Leeds 1-0 Milan (Sep 2000) A catastrophic error from Dida gave Leeds a crucial win courtesy of Lee Bowyer’s goal, with David O’Leary’s side going on to the semis Newcastle 1-0 Juventus (Oct 2002) Defender Andy Griffin was the hero as Newcastle beat Barça again, but they would gain their revenge in the next stage Internazionale 1-5 Arsenal (Nov 2003) A brilliant individual goal from Thierry Henry inspired a 5-1 rout at San Siro, but Arsenal failed to reach the knockout stages that year Juventus 0-3 Man Utd (Feb 2003) Substitute Ryan Giggs scored twice in the second group stage tie, only for United to be knocked out by Ronaldo’s Real Madrid Liverpool 3-1 Olympiakos (Dec 2004) Needing to win by two goals, Steven Gerrard’s late strike catapulted Rafael Benítez’s side through and onto victory in the Istanbul final Chelsea 1-0 Barcelona (Oct 2006) Didier Drogba scored the winner but Michael Essien was the star as Chelsea beat the holders before losing to Liverpool in the last four Tottenham 3-1 Inter (Nov 2010) The game that announced Gareth Bale’s arrival on the big stage. His brilliant hat-trick saw off the holders Man City 3-1 Barcelona (Nov 2016) After several years of trying, City got one over on Barça thanks to two goals from Ilkay Gündogan, after Lionel Messi’s opener

The result is a decadence among many of the leading sides, a focus on only one part of the game. As Tony Evans pointed out on the Second Captains podcast this week, fans have come to expect and demand entertainment and for some that has become a surrogate for winning. In practical terms, on the pitch, what it means is that elite sides have softer underbellies than they have ever had before. Genuine opposition is such a rarity that when they meet it they have no idea how to react.

That is why so many games between ostensibly well-matched elite sides end up with a surprisingly large margin of victory. The Barcelona-PSG last-16 tie last season – 4-0 to PSG in the first leg; 6-1 to Barça in the second – was the perfect example of that. It was thrilling but it was essentially two big men taking it in turns to hit a blancmange with an axe. Barcelona, it will be remembered, rapidly succumbed to a better-balanced Juventus in the following round.

In the past eight seasons, 21 games at the quarter-final stage or later of the Champions League have been won by a three-goal margin; in the eight seasons before that, there were only eight. Top sides, the elite who reach those stages of the competition, may be better than their forebears at attacking but the art of defending is being forgotten. There is too much attention on the glitter of glory and not enough on the guts.

Facebook Twitter Pinterest Kieran Trippier, here jumping over Casemiro, helped Tottenham to expose the space behind Real Madrid’s full-backs. Photograph: Adam Davy/PA

The one major league that is not – yet – subject to the Biscan Principle, is the Premier League. It is not just that six sides began this season with at least vaguely realistic title ambitions, it is that the bottom sides are still wealthy enough to compete – which is why the attempts of the Big Six to hive off more of the overseas television rights must continue to be resisted.

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For the past few years, English underperformance in Europe has been blamed on that competitiveness, on, as Louis van Gaal had it, the “rat race” of the English game. This season, although it is still early, the signs are that Premier League sides may be benefiting. Premier League sides have lost only one of 20 Champions League games this season, have collected 40% more coefficient points than any other league and, perhaps most impressively, have shown an intelligence and a tactical flexibility perhaps lacking in the past.

Mauricio Pochettino tweaked again, shifting from the 3-5-2 he had used in the Bernabéu to a 3-4-2-1. Madrid’s 4-3-1-2 shape demands the full-backs get forward to offer attacking width; Tottenham were merciless in exposing that, leading directly to the opening goal.

Madrid were limp, lazy and disorganised, still a threat going forward but a rabble at the back. Perhaps they were infected by the realisation they will almost certainly qualify anyway and that they won the competition after going through in second last season. But after their sluggish start to the domestic season there is reason for serious concern.

After successive defeats, Tottenham sides of the past might have wilted but not this one. Mentally they were tougher than Madrid and tactically they were smarter. Wednesday was a night that will live always in Tottenham’s history but it should also be a warning to Madrid and perhaps also the other super-clubs.