Step 1: Identify the 2026 FIFA World Cup hosts.
FIFA 2026 is the first-ever three-nation co-hosted tournament - USA, Canada, and Mexico share hosting duties.
Step 2: Recall the opening match venue.
The opening match is scheduled at Estadio Azteca in Mexico City on June 11, 2026, making Mexico the country that hosts the first game.
Step 3: Eliminate the distractors.
Brazil is not a 2026 host (it hosted in 2014). Canada and USA are co-hosts but the opening match privilege goes to Mexico's iconic Azteca stadium.
\[ \boxed{\text{Mexico}} \]