Bosnia boosted their confidence ahead of their first World Cup with a 1-0 friendly victory over Mexico on Tuesday that left 'El Tri' looking for answers.
Galatasaray midfielder Izet Hajrovic scored the lone goal of the match in the 41st minute after a strong first half from Bosnia.
Senad Lulic tracked the ball down in Mexico's area and slipped it through to Sejad Salihovic, who cut back to set Hajrovic up for the one-time finish.
"It's a good win for us," said Bosnia and Manchester City striker Edin Dzeko. "Now I think we're prepared for the World Cup."
The match before a sell-out crowd of 60,707 at Soldier Field, home of the NFL's Chicago Bears, followed Bosnia's 2-1 friendly win over Ivory Coast in St. Louis, Missouri, and was the country's last match before they head to Brazil.
Bosnia will open their World Cup campaign against Argentina on June 15, and will also play Iran and Nigeria in Group F.
Despite the backing of a partisan crowd, Mexico were punchless in attack as Javier "Chicharito" Hernandez found himself frustrated in front of goal despite some good looks.
The best of those came after his picture-perfect touch on Miguel Layun's long ball set him free on goal, only for his effort glance off the post.
Mexico, who lost midfielder Luis Montes to a broken leg in their previous match against Ecuador, were also without banged-up defender Rafael Marquez.
Mexico coach Miguel Herrera experimented with a new starting lineup with Hernandez earning his first start since the end of the Premier League season.
Herrera also gave Alfredo Talavera the nod at goalkeeper ahead of Guillermo Ochoa and the injured Jesus Corona, but Herrera will have plenty to think about as he looks toward a Friday friendly against Cristiano Ronaldo and Portugal in Foxboro, Massachusetts.
Herrera has said he wants his starting lineup against Portugal to be the same starting side he sends out for Mexico's World Cup opener against Cameroon on June 13.
Mexico will also face hosts Brazil and Croatia in Group A.