Brazil will be looking to get in good form again, after a weak start to the tournament. They've already knocked out Serbia and Costa Rica.
While Brazil have some injuries, Mexico's players are all fit for the match.
How they got here
Mexico started the tournament off great, with a win against previous world cup champions Germany (1-0). Then they played South Korea, in their second match of the tournament. The match ended in a 2-1 win for Mexico.
After two games, Mexico were first in their group, and things looked great for them. But when Sweden got their second goal, Germany only needed to win by one goal against South Korea. That goal didn't come.
In the last ten minutes of the match, the Koreans struck twice, knocking Germany out of the World Cup. Mexico finished second in their group on goal difference. Sweden finished above them.
After the draw for the group stages, things looked very good for the Brazilian national team. They had to play against Serbia, Switzerland, and Costa Rica. Their first game was against Switzerland. The game ended in a 1-1 draw. The Brazilians gave away their lead when Stephan Zuber headed in the equaliser.
That result made the second match crucial for the Brazilians. Brazil had some trouble with breaking down the Costa Rican defence. They scored the first goal of the match in the 92nd minute. Neymar added a second in the 96th minute. Brazil secured the three points in the last minutes of the game.
They then played Serbia, where they needed at least a point to advance to the last 16. They rolled over Serbia, winning 2-0, knocking both Costa Rica and Serbia out.
What to expect from this match?
The match has already been described as one of the most unpredictable matches of the tournament. Both teams are looking like they can win it.
Brazil need a strong performance, something that they've been unable to perform in their first two matches against Switzerland and Costa Rica.
Mexico will try to get back to the winning ways, after their 3-0 loss to Sweden. Some players have been outstanding for their side in the group stages. Players like Hirving Lozano, Phillipe Coutinho, or Carlos Véla have already proven to be very important to their teams.
Mexico currently don't have any injured players and have a full squad to choose from. Brazil could have some problems in the defence though, with both Marcelo and Fagner being out with injuries picked up in the group stage.