Inter have confirmed Alexis Sanchez has damaged a tendon in his left ankle while on duty with Chile and may now require surgery.
A superb first-half display from Northern Ireland was enough to secure a 3-2 win over the Czech Republic at the Generali Arena.
Chile coach Reinaldo Rueda believes Alexis Sanchez could be out for a prolonged period after suffering an ankle injury against Colombia.
Marcos Acuna impressed in Argentina's thrashing of Ecuador and Lucas Alario applauded his performance.
Neymar was withdrawn with a knock during Brazil's friendly against Nigeria, but Tite insists he was not a pre-match worry.
Drawing with Nigeria is an "insufficient" result for Brazil but head coach Tite took heart from a stronger showing after half-time.
Ecuador were no match for Argentina on Sunday, as Lionel Scaloni's La Albiceleste claimed a comfortable 6-1 friendly win in Elche.
Chile have confirmed Inter forward Alexis Sanchez, on loan from Manchester United, damaged his left ankle in a game against Colombia.
Paris Saint-Germain star Neymar was substituted in the 12th minute of Brazil's clash with Nigeria due to a suspected hamstring issue.
Lionel Messi is serving a suspension handed down following the Copa America.