Stanford's Kelley O'Hara led the Americans with a hat trick against Cuba. Portland's Michelle Enyeart scored twice after coming on as a substitute against Cuba and added a goal against Mexico to give her six goals in three games.
O'Hara opened the scoring in the 10th minute against Mexico and Enyeart and Nikki Washington added second-half goals. Washington scored two goals against Cuba.
The USA will play Costa Rica, who finished in second place in Group B, on Wednesday in the tournament semifinal with a berth at the Under-20 Women's World Cup in Chile on the line. The other semifinal features Group B winner Canada against Mexico in the second game of Wednesday afternoon's doubleheader.
"Mexico provided a very big test for our team today," said U.S. coach Tony DiCicco. "Playing Mexico will help us prepare for Costa Rica. Both teams have good, smart and quick players who are dangerous with the ball. So, hopefully playing Mexico today will make us a better team as we head into Wednesday's game against Costa Rica."
June 20 in Puebla
USA 9 Cuba 0. Goals: Morgan 2, Washington 33, 43, O'Hara 46, 54, 80, Enyeart 59, 66, Edwards 72.
USA -- Arnold, Dallstream (Leroux, 59), Fountain, Marshall, Klingenberg, Edwards, Wells, DiMartino (Nairn, 46), Morgan (Enyeart, 37), O'Hara, Washington.
Cuba -- Martinez, Beyerano, Lopez, Alvarez, Fuentes, Valdes (Blanco, 90), Carp, Hernandez, (Bernal Chacon, 46), Reyes, Rodriguez, Gallardo.
June 22 in Puebla
USA 3 Mexico 0. Goals: O'Hara 10, Enyeart 67, Washington 88.
USA -- Naeher, Dallstream, Fowlkes, Marshall, Klingenberg, Edwards, Nogueira, (Nairn, 77), Winters, Leroux (Morgan, 46), O'Hara (Washington, 62), Enyeart.
Mexico -- Venagas, Mendoza, Gomez (Martinez, 38), Mercado, Mondragon, Garza, Palma, Yorres (Hernandez, 57), Godoy (Romero, 75), Corral, Mayor.
USA 4, Trinidad & Tobago 0
Mexico 7, Cuba 0
USA 9 Cuba 0
Mexico 3, Trinidad & Tobago 0
Trinidad & Tobago 4, Cuba 0
USA 3, Mexico 0
Canada 2, Nicaragua 0
Costa Rica 3, Jamaica 1
Canada 3. Jamaica 1
Costa Rica 3 Nicaragua 2
Jamaica 6, Nicaragua 0
Canada 4, Costa Rica 0