It was the biggest upset ever in women's soccer, maybe even the biggest in the history of international women's sports.

When the United States took to the field against Mexico last November in the semifinals of the CONCACAF championship, most expected the Americans to stroll to victory and claim a berth at this summer's FIFA Women's World Cup. But the Mexicans, buoyed by the Cancun crowd, deviated from the script and stunned the Americans 2-1 to book their plane tickets for Germany.

How big of an upset was it? 

Consider this: the Americans, two-time World Cup winners and the defending Olympic gold medallists, were 24-0-1 all-time against Mexico and 54-1-6 in all competitions since the 2007 World Cup. What's more, the U.S. recorded 21 consecutive victories going into the Mexico match, and had outscored their opponents by a whopping 131-3 margin in World Cup qualifying in over 20 years of competition.

The loss to Mexico forced the U.S. to beat Costa Rica in the tournament's third-place game, and then Italy in a two-game playoff, which they narrowly did by an aggregate score of 2-0. 

The No. 1 ranked nation in the world became the 16th and final country to qualify for the World Cup. A dominant force in the women's game for over two decades, the U.S. had fallen from grace, and now, with the World Cup looming, everyone is questioning their credentials and whether or not they are a fading power.

According to American forward Abby Wambach, it's not a matter of the U.S. national team being on the wane or vulnerable. It's about the narrowing of the gap between the sport's traditional heavyweights and the rest of the world.

"I'd say vulnerable wouldn't be the feeling I have. It is clear that the game has evolved, and it is clear any team can win the World Cup," Wambach told CBC Sports. "Any team that has qualified has a chance. There are going to be some favourites and some teams that look like they have an easy road [but] there will be some upsets in this World Cup.

"So many countries have put money into their programs and women's soccer in the world is growing and the game has changed. I'm excited to see what is going to happen."

Fellow forward Alex Morgan echoed Wambach's sentiments, pointing to the expansion of the World Cup from 16 to 24 teams for the 2015 tournament in Canada as evidence of women's soccer being more competitive. 

"That's a big deal, a big step in women's soccer and women's sports in general. Being able to live through that and see how competitive it is now that they need to add more teams for the next World Cup is amazing and it's great to be a part of that journey," Morgan stated.

American midfielder Heather O'Reilly believes that the Americans' back-door route to this summer's World Cup served as a bit of a wake-up call for the team.

"It was definitely an unorthodox route to qualifying," admitted O'Reilly. "We've experienced a few more bumps along the road than this program is used to, but of course we're looking at that as a positive and growing experience… We've learned and grown from these knocks we've taken and we're hoping that leads us to peaking at the right time in Germany."

It wasn't that long ago that the U.S. outscored their opponents by five or six goals, and matches were won before a ball was even kicked, such was the intimidation factor working in the Americans' favour.

Those days are over, claims forward Amy Rodriguez: "At the end of the day, you really have to work hard [because] every team at the World Cup is so talented. We need to show up."

Germany represents a major test of the Americans' will and character, a chance for them to prove that despite recent setbacks they are still among the sport's elite.

"We have to evolve our game and so I think as you see Tiger Woods trying to change his swing, sometimes he suffers for a little but then he gets better," said defender Stephanie Cox.

"We have to believe in what we're doing and what [coach] Pia [Sundhage] wants us to do as the team as a whole and once we do that, we have the talent to fulfill the vision that she has for us."

The key to success for the U.S., explains Cox, is the team's overall depth and ability to rely on several veteran players, such as Wambach.

"We have a core group of players who have played under Pia and I think that's comforting," said Cox. "Probably what we hold onto is the strength in our depth. I think we're such a deep team, deeper than we've been in the past, so I think that's something that's unifying, strengthening and encouraging."