Inter Miami will face Ahly in the opening match of the expanded tournament, which for the first time features 32 teams.
On Saturday, Miami delivered a dominant 5-1 victory over Columbus Crew in MLS action, with Argentina legend Lionel Messi contributing two goals and three assists in a standout performance.
Mascherano stressed that the win was important for building confidence ahead of the Club World Cup but stressed that his team would need to put in even more effort, given the strength of their group.
Inter Miami are drawn into a challenging group alongside Ahly, Brazil's Palmeiras and Porto of Portugal.
“This victory shows us that if we stay brave and composed, we can compete with any team, especially in MLS,” Mascherano said in the post-match news conference.
“But the Club World Cup is a different level. The competition is much tougher, and I must be realistic — including Al Ahly.”
“People may think they’re a weaker opponent, but I’m telling you, they’re not. Far from it. We’ll compete, stay true to ourselves, and not fear mistakes. We have to keep pushing forward.”
Inter Miami are led by Messi, along with former Barcelona teammates Jordi Alba, Sergio Busquets, and Luis Suárez, under the guidance of Mascherano, who took charge of the team earlier this year.
Ahly are one of four African teams in the competition, alongside South Africa's Sundowns, Tunisia's Esperance de Tunis, and Morocco’s Wydad de Casablanca.
After facing Inter Miami, Ahly will meet Palmeiras on Thursday 19 June, before concluding their group stage against Porto on Tuesday 24 June.
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