EDMONTON, Alberta — It began as a fascinating match of the establishment against the insurgent, an evolutionary tug of war in women’s soccer, with the United States trying to maintain its hold as a traditional power and Colombia trying to break through to a new era of parity.

And for a half on Monday, aspiring Colombia held the Americans scoreless in their round-of-16 game at the Women’s World Cup with a fearless young goalkeeper named Catalina Perez, a redshirt sophomore at the University of Miami who is but 20.

Then recklessness and inexperience trumped assurance for Perez, who was given a red card in the 47th minute for sweeping out the legs of Alex Morgan at the edge of the penalty area.

Playing a woman down, Colombia became vulnerable, and the United States prevailed, 2-0, before a sparse crowd announced at 19,412 with goals by Morgan and Carli Lloyd and, more reliably, with a defense that has not let the ball into the net for 333 minutes.