Mexico beat the USA for the first time in 14 years, 2-0 at the CONCACAF W Gold Cup Group A decider in Carson, California.
It was only the second time in 43 matches between the national teams that Mexico have come out on top.
Jacqueline Ovalle opened the scoring late in the first half, when charging down an attempted clearance by goalkeeper Alyssa Naeher.
Mayra Pelayo made sure of the victory in style during added time, with a rocket from outside the box inside the far post.
Third-placed Argentina kept up hopes of following the top two into the quarter finals, with a 3-0 defeat of Dominican Republic.
Canada made it two wins from two in Group C, beating Paraguay 4-0 with Adriana Leon hitting a hat-trick and Olivia Smith netting the other goal.
Costa Rica got off the mark, as Priscilla Chinchilla got both goals of the game against El Salvador.
