FRISCO, Texas -- The U.S. women's soccer team's younger reserves not only didn't disappoint in their Group A finale in CONCACAF qualifying for the Rio Olympics, they delivered a record performance.
Crystal Dunn, one of only three regulars to start, tied a national team record with five goals, and the U.S. routed Puerto Rico 10-0 Monday night to win the group.
"I'd like to think this is a special moment," said Dunn, who couldn't recall another five-goal game during her entire soccer career, "but I'd love to think there's more to come."
"Crystal worked real hard tonight," U.S. coach Jill Ellis said. "She was in a good position in central; I think that's probably her most comfortable position. Obviously, got a lot of service from her teammates. It's tremendous for her and for her confidence."
The top-ranked Americans scored three times within 1:56 during the second half and outshot Puerto Rico 32-1.
The U.S. can clinch one of the 12 slots in Brazil with a win in its CONCACAF semifinal game Friday in Houston. It will face the runner-up of Group B, which will finish play Tuesday. Canada is expected to win that group, with Guyana or Trinidad & Tobago finishing second.
The U.S. remained unbeaten in all-time CONCACAF qualifying play at 16-0-1, having scored 91 goals and allowing four.
The tournament is the Americans' first competitive play since winning last summer's World Cup in Canada. They have won three straight Olympic titles and four of the five that have been staged in women's soccer.
Group A's other semifinalist is Costa Rica, which edged Mexico 2-1 in Monday's first game at Toyota Stadium.
Dunn's scores came in the sixth, 21st, 62nd, 85th and 87th minutes. She had five career goals going into the game and became the seventh U.S. woman to score five in a match.
The other five goals came from Carli Lloyd (on a penalty kick), Kelley O'Hara, Christen Press, Samantha Mewis (her first career score) and on an own goal.
Ellis' opening lineup included eight players who didn't start either of the two previous group games and only five players who appeared in last summer's World Cup. The lineup was drastically changed since the team had already clinched a semifinal spot, was playing for the third time in five days and faced an opponent ranked No. 108.
Alex Morgan played only the second half, substituting for Lloyd. Goalkeeper Hope Solo was among the regular starters rested.
The newcomers included Mallory Pugh, 17, the youngest American woman to start a qualifying match. Pugh assisted on Dunn's first goal and was tripped in the 18th minute, leading to Lloyd's penalty kick.
"As the game kind of went on, I kind of got more comfortable with the ball," Pugh said. "I think that the fact that my teammates around me are so positive, that helps."
"This squad that we started today was obviously young," Dunn said. "I think it was really great for everyone to get some time today."
Alyssa Naeher earned the shutout, the third of her career, in her first CONCACAF qualifying appearance.
It was Lloyd's 85th career international goal and 11th in Olympic qualifying, three off Abby Wambach's U.S. record.
O'Hara's score came on a back heel near the goal line in the 45th minute off a cross from Stephanie McCaffrey.
Puerto Rico made its first appearance in the CONCACAF qualifying tournament and had never previously faced the United States at the senior level. It was outscored in its three matches 25-0.
This U.S. roster features only 13 of the 20 players who were on the World Cup team. Christie Rampone and Megan Rapinoe are injured, and Amy Rodriguez and Sydney Leroux are pregnant and will miss the Olympics.