Whatever happens in the remainder of this tournament, and whether or not they lift the trophy, you suspect there will be echoes of Ajax’s class of 2019 reverberating around European football for many years to come.
Having already won in Madrid and Turin, they brought their refreshing, youthful style of football to England and enthralled a global audience once again with an excellent away win, one which also required defensive steel as Tottenham fought back strongly in the second half.
It may not have been what Spurs fans were hoping to see on their big night but coaches, managers, and scouts across the world were almost certainly jotting down notes as they watched it all unfold.
There’s something different, something remarkably modern about this Ajax side.
Not that everything they do is pretty or based on the ideal of beautiful football — and that makes them significant, too.
Erik ten Hag’s side work in packs to win the ball back high up the park and contrast their flicks and fast feet in attack with a ruthless, structured, and solid defending style at the back, as exemplified by Joel Veltman last night.
We saw all sides of their game in London and despite Tottenham’s lack of attacking quality — they badly missed Harry Kane and Heung min Son — it was a proper test for such a young side and augurs well for their future.
Many of of these players are not yet big names (or certainly weren’t going into 2018-19). Many are barely into their 20s and most are too young to have won trophies or are having to rebuild their careers in Amsterdam having failed to do so elsewhere.
But now they are part of a once-in-a-generation team that have the potential to make an impact on European football long into the future.
Not because they are likely to be together for years like the Ajax team of the ’70s — sadly the reality is they will be sold off one by one to the likes of Barcelona, Real Madrid, and PSG over the coming seasons — but because their performances could mark a changing point in football history.
We’ve seen it before with the Barcelona era of tiki taka.
We’ve seen it with three-at-the-back in the Premier League last season, with Manchester City’s pass-and-move and Liverpool’s German-inspired heavy metal football.
When something works for one team, others follow and trends change.
Next season, you can be sure there will be clubs across Europe trying to recreate the Ajax style of youthful, fast-paced attacking football — something Gareth Southgate is already trying to do with the England national team.
The average age of teams may well come down, there will be greater emphasis on short, sharp passing on the edge of the penalty area, greater focus on the speed of pass in the build-up, and a more pragmatic approach to defending.
If that happens then we are all in for a treat because watching Ajax 2019 attack is like watching Ajax 1971 but with the fast-forward button permanently pressed down.
In fact the only time they slowed in the first half was when Donny van de Beek scored with a coolness and calmness out of kilter with the intensity of everything else he did.
The average age of this Ajax side is little more than 25 (and that takes into account 29-year-old defender Daley Blind and 32-year-old midfielder Lasse Schone), but inexperience seems to mean nothing to them.
In their first Champions League semi-final in 22 years, they barely showed a moment of nerves, even when Spurs changed formation and posed a far bigger threat in the second half.
Perhaps that is why the biggest clubs in the world are looking at cherry-picking the heroes who have played so well in this year’s tournament.
Barcelona have already secured the signature of €80m Euro midfielder Frenkie de Jong, tipped as the long-term replacement for Sergio Busquets, and described as Franz Beckenbauer with a touch of Johan Cruyff, which is quite some accolade.
Outstanding defender Matthijs de Ligt, who is only 19 and who showed a real coolness of head in a tough second half, has been linked with Liverpool, Manchester United, and Barcelona.
Attacker David Neres (who hit the post with a big chance for 2-0) interests Arsenal and Juventus, while Van de Beek is coveted by Chelsea and Tottenham, who also like Hakim Ziyech.
The list, to be honest, is probably far longer than that but you get the picture — teams across Europe will have an Ajax influence next season whether that is achieved by incorporating their players or by copying their tactics.
Until then, however, we can just sit back, enjoy the show, and wait for what should be a fascinating second leg in Amsterdam.
There is history in the making and you suspect it will be Ajax, not Spurs, who provide it.