Kone's harrowing injury happened in the 55th minute after a challenge from Assim Madibo, and his teammates' immediate reactions suggested it was incredibly serious.
He was stretchered off the pitch, needing oxygen and painkillers, after being treated for a few minutes, and Marsch, who was close enough to hear the bone snap, admitted the injury shook his whole side.
Speaking about Kone to Flashscore and assorted media, Marsch revealed that Kone was "at the hospital and is preparing for surgery."
"It happened right in front of the bench; we could all hear it. Your heart goes out to him, and everyone is a little shaken by the whole experience, because of the nature of the injury and because Ismael is a big part of the heart of our team.
"It will be a big loss for us. He's been an amazing player for us in the last two games, but he was waving to the crowd and making everyone else feel at ease with the fact that he's injured, and it's an incredible statement about Ismael as a person, but also this is our team.
"... Everybody was crushed when it happened, but we had to find a way to stay focused.
"We're very proud of what we are and who we are - that was on show today."
Madibo apologised
The incident was reminiscent of that suffered by Tajon Buchanan in 2024. In training ahead of the 2024 Copa America, the Villarreal winger broke his tibia, forcing him to miss six months of action.
The Canada manager also revealed that Madibo had been to the dressing room to apologise for the challenge, and the 52-year-old felt the game was not too physical despite Qatar ending the game with nine men.
"Until the injury, I thought that the match was pretty good. We had a very dominant performance in the first half, and I think, probably, their coach (Lopetegui) wanted to fire them up a bit at half-time, to give them a chance to not go down by four, because that means they have to beat Bosnia.
"We were aware of that, and we needed four so we don't have to beat Switzerland. I think that led to the (challenge).
"Let me be clear, the player (Modibo) apologised to Ismael. He came into the dressing room and apologised to him, and Ismael told the team.
"I don't think that he meant such a gruesome tackle or such a gruesome situation. I don't fault him for that..."
'Seminal moment'
Canada's big victory was a historic one. It was their first in the World Cup finals, and Marsch celebrated it wholeheartedly after the final whistle, alongside the team and the fans in the stands.
"No Canadian will forget this day. There will be 40 million people who will say they were here.
"It's an incredibly seminal moment for everyone to understand the talent in this country, that there is mentality, there is desire, there are a lot of things that make this country special...
"I'm very proud of what we have accomplished, a moment that people can remember, but this will drive us to do everything we can to win the group and make a run at this tournament."
After picking up three points, Canada moved to the top of Group B on goal difference over Switzerland, whom they face in their final group game on June 24th. If they can avoid defeat, they will finish top of the group, allowing them to play at Vancouver once again.
That is now the challenge for Marsch and his players - but first, they will enjoy a family barbecue on Friday.
Read the analysis from the game with Flashscore.
Josh Donaldson is a Global Senior Editor and International Football Specialist for Flashscore. From the UK, now living in Prague, Josh specialises in football and cycling and can be found at an obscure ground watching games or on his bike. You can follow Josh on X and read his articles here.
