Montreal:Mexico defeated New Zealand 2-1 and moved into the second round of the Under-20 World Cup on Sunday as the only team to win its three group matches.
Gambia finished second to Mexico in Group C by beating Portugal, also by 2-1. All three bar first-time participant New Zealand advanced.
Chile topped Group A after drawing Austria 0-0, and both advanced with Congo, a 2-0 winner over eliminated Canada.
In Wednesday's second-round matches, it's: Austria vs Gambia, United States vs Uruguay, Spain vs Brazil, and Japan vs Czech Republic. On Thursday, it's: Chile vs Portugal, Zambia vs Nigeria, Argentina vs Poland, and Mexico vs Congo.
Mexico's first goal came when Javier Hernandez's shot bounced out of New Zealand goalkeeper Jacob Spoonley's hands and Christian Burmedez pounced on the loose ball at Edmonton. Osmar Mares scored the decider before Jack Pelter put in a rebound for the Kiwis in the last minute.
Gambia played the last 31 minutes against Portugal with 10 men after defender Ken Jammeh was sent off for a foul that forced Andre Marques out with a left leg injury in Montreal.
However, Gambia broke a 1-1 deadlock in the 68th when Abdoulie Mansally converted his free kick.
Portugal scored first through Feliciano Condesso in the 20th, and Ousman Jallow leveled off a penalty a minute before halftime.
Chile and Austria fought to a scoreless draw in Toronto, and qualified for the second round. Chile didn't concede a goal in group play.
Congo ensured host Canada was the only team to finish the group phase without scoring.
The Congolese went ahead on Ermejea Ngakosso's goal in the 26th minute in Edmonton, then took advantage of Canada's desperation in the rain when Gracia Ikouma scored in the 60th.
In a bizarre development, Canada goalkeeper Asmir Begovic was sent off for handling the ball outside his box in the 73rd, and a midfielder stepped in goal because Canada had used all of its substitutes.