The glitzy Tottenham Hotspur Stadium played host to the heavyweight showdown with 70,000 expectant fans present for one of the biggest combat sport events since the onset of the pandemic.
However, those fans did not get what they expected at all as Usyk put on a heavyweight masterclass under the capital city lights.
Usyk was dominant from start to finish, systematically picking AJ apart as he built towards a deserved win.
By the time the fight had gone the distance, there was no doubt that we would be crowning a new heavyweight world champion as Joshua struggled to cope with the Ukrainian onslaught.
AJ looked laboured and devoid of a definitive plan while Usyk came prepared and executed his tactics to absolute perfection.
What it means is that, for the second time in his career, AJ has lost his prestigious titles in a fight that, before the first bell, he was considered the overwhelming favourite.
It also casts a devastating cloud of doubt over any potential 'Battle of Britain' fight with Tyson Fury, especially when you consider the new heavyweight rankings that are emerging in the aftermath of the London debacle.
The kings of the ranking, Ring magazine, have released their new heavyweight and pound for pound lists with Usyk making some major moves following his superb showing on Saturday night.
Ring Magazine's heavyweight rankings:
C. Tyson Fury
1. Oleksandr Usyk
2. Anthony Joshua
4. Dillian Whyte
5. Joseph Parker
6. Andy Ruiz Jr
7. Luis Ortiz
8. Michael Hunter
9. Oscar Rivas
10. Joe Joyce
Usyk also saw himself leap up the rankings in the pound for pound category. There is still, however, much work to be done if he wishes to usurp Canelo Alvarez at the top.
Ring Magazine's pound-for-pound rankings:
1. Canelo Alvarez
2. Oleksandr Usyk
3. Naoya Inoue
4. Terence Crawford
5. Josh Taylor
6. Errol Spence
7. Teofimo Lopez
8. Juan Estrada
9. Vasyl Lomachenko
10. Kazuto Ioka
It looks as though Joshua will now move to exercise his rematch clause with Usyk as he bids to right the wrongs of a forgettable night in the capital.
Elsewhere in the heavyweight world, Ring magazines champion Fury is preparing for his third fight with third ranked Deontay Wilder.
Fury is currently the favourite to retain his titles and keep his spot atop the rankings but, when Wilder's right hand is involved, anything can happen.