The sound rang out around the Khalifa International Stadium. Some fans still hadn't found their seats but, even if the pitch wasn't in view, they would have heard the moment Alphonso Davies and Canada created history.
It was just over a minute into Sunday's group stage clash with Croatia and, after losing 1-0 to Belgium in their opener, it appeared Canada had learned their lesson. They were wasteful then, but they wouldn't be tonight. Davies headed home Tajon Buchanan's cross and the crowd erupted; Canada had scored at the World Cup for the first time and were in the lead.
But this inexperienced Canadian team learned another harsh lesson on Sunday. Facing a team that knows better than most what it takes to go far in this tournament, Canada's naivety, on the field and off, was put on full display. Because of that, their World Cup dream is now over.
In the end, Croatia ran away with it, dominating the 89 minutes or so that followed Davies' heroic opener. It finished 4-1, with two goals from Andrej Kramaric and one each from Mark Livaja and Lovro Majer.
Croatia have many things Canada do not. They have experience, know-how and guile. They may not have the pace, but they have the brains. And, ultimately, they also have Luka Modric, a player that can dictate where and how a game is played better than most we've ever seen.
Canada have none of those things, at least not yet. They may never have a Modric of their own, although one would be nice. But, on the road to their own World Cup in 2026, Canada have been dealt another harsh lesson about what it means to play at this level.