Barcelona and Juventus were set to take on one another at the Levi's Stadium in Santa Clara in front of a sellout crowd in the United States.
But nine hours before kick-off, the game was cancelled after a virus outbreak that forced those afflicted to seek medical help.
A statement from Barcelona read: "Barcelona hereby informs that the game against Juventus, scheduled for today, July 22 at 7:30pm at Levi's Stadium, as part of the Soccer Champions Tour, has been cancelled.
"A significant part of the Blaugrana squad has viral gastroenteritis."
According to Sport, four players were left 'seeking medical help' as a result of catching the bug.
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Alejandro Balde, Eric Garcia, Jules Kounde and new signing Oriol Romeu were all reported to have been struck down by the virus.
The outbreak has caused major disruption to both Barcelona and Juventus, as well as the many fans who had been excited to see the European superpowers in action.
Juventus have, instead, made their way to San Francisco to train instead and might change their schedule.
They are due to face AC Milan next Thursday in Los Angeles but Juve might fly out earlier than expected.
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On the other hand, Barcelona will face Arsenal in Inglewood, California on Wednesday night.
They are not the only mega-clubs in the United States this summer, where Manchester United, Chelsea and Real Madrid also have made the trip.
Both clubs have been busy in the transfer window this summer.
Barca have signed four players, including the aforementioned Romeu.
The Spaniard came up through Barcelona's La Masia academy and has been tasked with replacing Sergio Busquets.
Ilkay Gundogan and Inigo Martinez have also joined, all three on free transfers.
Meanwhile, Juve have signed Timothy Weah from Lille to bolster their attacking options.
Manuel Locatelli has also joined permanently after two years on loan, as well as Moise Kean and Arkadiusz Milik, who were also on loan last season.