When soccer’s best two teams in the world meet this Sunday for the finals of the Women’s World Cup, the “beautiful game” will live up to its name for fans and sponsors alike. The U.S. is in it this year, facing Japan, rousing extra enthusiasm for viewers and ratings at home.

But after the game is over and the fans have changed the channel, it’s going to be another four years before another World Cup. What happens to women’s soccer in the U.S. until then?

Many global players have already migrated to Women’s Professional Soccer, the top-tier league for women in the U.S. that consists of six professional teams. Just three seasons old, WPS began with only two sponsors, Puma and Citi. It now boasts nine — but its financial worries are far from over.

Since forming in 2009, WPS has faced its fair share of highs and lows. This past November, FC Gold Pride, the league’s only West Coast team, disbanded after facing financial difficulties. Meanwhile, 2011 attendance per game dropped almost 13% from last year. A number of sportswriters say the league is on life-support, echoing the demise of a previous U.S. women’s soccer league, the Women’s United Soccer Association, which only lasted three seasons from 2001 to 2003.

It’s not the same situation, says WPS CEO Anne-Marie Eileraas. Like any startup, WPS has seen its share of troubles. But unlike the WUSA, she and her executive team believe the newly created league has realistic expectations.

WUSA’s model was built “coming off of the success of the 1999 World Cup,” according to WPS CFO Kristina Hentschel. With marketable players like Brandi Chastain and Mia Hamm it seemed like the perfect time to start a women’s soccer league.

But, the expectation bar was set too high. During the ’99 Women’s World Cup, the Rose Bowl overflowed with fans. WUSA expected to see similar attendance numbers at its league games, hoping the excitement of a Cup held in the U.S. would overflow into the following months. Unfortunately, it did not. WUSA had difficulty filling the huge stadiums and faced marketing troubles. After a three-year run, the league hung up its cleats for good.

The Women’s Professional Soccer League beginnings could not be more different than its defunct big sister’s. The League was founded in 2009. There was no global obsession with females playing the sport, the country was in a harsh recession, and household players like Hamm were no longer active. Instead, its founders acknowledged a surplus of talented female soccer players in the U.S. and their need for a way to play the game.

During its very short lifetime, WPS has cautiously monitored every misstep and learned from its mistakes. Hentschel cites the league’s openness to redoing the business model at any given point. Flexibility, she says, is key to its success.

A hybrid single entity model, WPS works with individual teams. Each team’s survival is contingent on ticket sales. According to Hentschel, the WPS League office will be profitable in 2011. But WPS teams, which are owned and operated by independent owners or ownership groups, are still working to realize profitability. “A post-Women’s World Cup increase in ticket sales would help the teams move closer to break-even in 2011,” she says.

Brandi Chastain, a member of the famous 1999 Women’s World Cup Team, believes WPS needs to capitalize on the post-Cup wave, while pointing to the constant struggle of women’s sports to gain a foothold in the U.S. “The League is not a sure thing,” she says. “It’s still disappointing to think that we need these [World Cup] moments to get people talking. It’s a never-ending cycle for women’s sports.”

In order to keep excitement up surrounding women’s soccer, Chastain believes the players “are integral and imperative to [WPS’] success.” The recognizable names — like Megan Rapinoe and Abby Wambach — need to be marketed. But many of the league’s top players have to leave soon to train for the Summer Olympics, so lesser known players need to step up and become familiar faces in the community.

WPS CEO Eileraas is a step ahead of Chastain. WPS has two marketing campaigns it hopes will create an increase in ticket sales in the upcoming months. “Extraordinary Heroes” celebrates the return of the World Cup players to their league teams. “Hometown Heroes” celebrates the players that have played in their local communities their entire lives — such as Philadelphia Independence’s Sinead Farrelly. Although she’s not well known on the global field, local fans loves watching her play.

Hentschel is also setting realistic expansion goals. Don’t expect to see new League teams popping up all over the country. “WPS is built on [a] grassroots premise: the highest level of play in intimate stadiums with players connecting on a personal level with the fans,” she says.

In order to ensure an authentic fan experience, Eileraas says WPS has no plans to “change radically in the near future.” The smaller stadiums allow fans to feel connected to players. Players’ individual Twitter accounts increase their visibility in the community and make for cheap marketing. This scrappy — as Eileraas calls it — way of running the league allows it to focus on what’s most valuable: deepening WPS’ relationship with the community, which creates loyal fans and consistent ticket sales. “No one will ever leave a WPS game without an autograph,” boasts Eileraas.

“The League is the best kept secret in sports,” she adds. With the hype surrounding the Women’s World Cup, “we’re letting the rest of the world in on it.” As Americans watch the U.S. Women’s Soccer Team this Sunday, it’s no doubt that the secret is out. But will it evolve into a lasting shout or remain a national whisper?