Gustavo Ayon scored 16 of his 38 points in the fourth quarter and Mexico overcame a 15-point deficit to hand Argentina its first loss of the Olympic qualifier, 95-83 on Wednesday night in the last game of the second round.
Mexicans earned the No. 2 seed and will face Argentina again Friday night in the FIBA Americas semifinals.
Earlier, Canada beat the Dominican Republic 120-103 to finish first and will play Venezuela in the other semifinal.