Striker Oribe Peralta combined with Tottenham forward Giovani dos Santos to score the only goal of the game against Switzerland on Wednesday and secure a place for Mexico in the Olympic men's football quarterfinals.
The result eliminated Switzerland from the competition.
Mexico will now play either Britain, Senegal or Uruguay, which play their final round of group matches later Wednesday.
Peralta and dos Santos, who scored two goals after coming on a substitute against Gabon in Mexico's last match, looked dangerous throughout much of the match and could have each scored more. Their form will give the South Americans hope of a medal in the competition.
Switzerland, needing to win by two goals to progress, created most of the chances in the first half as Mexico took time to settle. But the Europeans, whose build up to the game was disrupted when defender Michel Morganella was sent home after sending a racist tweet, were unable to breakdown a Mexican defense that has yet to concede in the tournament.
Swiss forward Innocent Emmeghara shot wide after Mexico lost possession in its own half, then goalkeeper Jose Corona did well to stop a dangerous cross across the box. Admir Mehmedi thought he had penalty after a forceful tackle, but referee Ravshan Irmatov gave a goalkick.
Still, the best opportunity of the half fell to Mexico with three minutes remaining. Peralta flicked the ball to dos Santos on the edge of the area. Dos Santos controlled the ball, but his powerful shot went straight at keeper Diego Benaglio.
In the second half, Mexico opened up and Switzerland's defense failed to mark its attackers.
The goal came on 69 minutes after sustained pressure. Dos Santos dribbled at the Swiss defense and then laid the ball on to Peralta, who fired a powerful shot to the right of Benaglio.
With qualification secured, Mexico played freely, and could have scored two more goals.
On 80 minutes, Benaglio tipped a swerving shot from substitute Israel Jimenez onto the crossbar.
