Although the 2016 Olympic Games opening ceremony isn't until Friday night, the men's and women's soccer tournaments are already underway.
Every team has played one game to this point, which is huge considering there are only three group-stage matchups before the knockout round. Any squad with a loss or even a draw could have a lot of ground to make up if it wants to stay alive.
The medals won't be handed out until the final few days in Rio de Janeiro, but here is what you need to know going forward as the top teams in the world fight for gold.