How the tension built
The night turned on the 53rd minute. Qatar midfielder Assim Madibo lunged into a reckless challenge on Koné, who went down with what proved to be a broken left leg. He was carried off on a stretcher and taken to hospital, now facing up to a year out. A VAR review upgraded Madibo's card to a straight red, Qatar's second dismissal, after Homam Ahmed had gone in the first half for a foul on Tajon Buchanan.
Down to nine, Qatar were overrun. But it was what Canada did with their advantage that lit the fuse. Even four goals up and two men to the good, the hosts kept pressing for more — goalkeeper Maxime Crépeau was spotted deep in Qatar's half in the 99th minute as Canada hunted a seventh — and Lopetegui was incensed on the touchline.
What happened at the whistle
It boiled over seconds after full time. Marsch celebrated with the home crowd, then turned to Lopetegui for the handshake; the exchange was frosty, words were traded, and the Qatari bench reacted. Within moments players and staff from both camps were pushing and shoving near the touchline before security and officials waded in to separate them.
Canada had their own grievances, having grown frustrated with a string of heavy challenges that culminated in Koné's injury. His teammates had surrounded him protectively as he was treated. Marsch refused to discuss the confrontation afterwards: "I'm not spending one second discussing it," he said, though he branded Qatar's conduct "strange." Lopetegui offered a weary verdict on the night as a whole: "It was a tough match, because everything that could go wrong, did go wrong."
A historic night, overshadowed
The brawl overshadowed a milestone result. Canada's 6-0 win was their first ever at a World Cup, and it all but secured a place in the knockout round.
David's treble made history. He became the first player from a host nation to score a World Cup hat-trick since Geoff Hurst did it for England in the 1966 final. The three goals also drew him level with Lionel Messi as the only players to score three in a single match at this tournament.
Cyle Larin opened the scoring on a rebound in the 16th minute after goalkeeper Mahmoud Abunada parried David's volley. David added a second on 29 minutes and a third in first-half stoppage time. Mohamed Manai deflected into his own net in the 75th for the sixth.
The match drew high-profile attention. Canada Prime Minister Mark Carney watched alongside FIFA President Gianni Infantino, having missed the team's opener in Toronto because of the G7 summit in France.
Lopetegui's wider task
The defeat lands on a Qatar side already under strain. Lopetegui brought 26 players to the tournament after preparations were hit by bombings and a shortage of competitive matches.
Before arriving in the United States, Lopetegui set out his standard plainly. "...going to the World Cup just for the sake of going is stupid," he said. A 6-0 defeat, two red cards and a touchline melee have made the road ahead steeper still.