“Physically they are very strong. We are preparing for a war as we know there will be a solid three against three in midfield,” said Wilmots.
Belgium’s attacking midfielder Kevin De Bruyne, who celebrated his 23rd birthday on Saturday, concurred with his coach’s opinion.
“Personally I think it will be a physical combat. They are physically strong and will push themselves to the limit,” said De Bruyne.
“We cannot compare this game to the friendly last year which we won 4-2. Besides we are playing a knockout match which is completely different.”
Belgium, whose best performance at a World Cup was reaching the 1986 semi-finals, topped Group H with three wins from three games while the United States finished runners-up to Germany in Group G.