Jonathan Zimmerman, who teaches history and education at New York University, taught in NYU's study-abroad program in Ghana in 2008 and 2009.

I'm an American, but I used to live in Ghana. So last Saturday's World Cup match between the two countries presented a sports-fan dilemma: Should I support my own country or my adopted one?

I rooted for Ghana. And so should you, now that you've absorbed the shock of its 2-1 victory over the United States.

The first reason is the simplest: Ghanaians love America. In a 2009 survey by World Public Opinion, 76 percent of Ghanaians reported a "mainly positive" view of the United States' influence in the world. Compare that with France (36 percent), Germany (18 percent) and Russia (7 percent), and you'll get the idea. Only 60 percent of Americans in the survey said our influence was positive - by that measure, Ghanaians like us more than we like ourselves.

Their pro-American sentiment goes back to Ghana's founding leader, Kwame Nkrumah, who spent 10 years in the United States earning degrees from Lincoln University and the University of Pennsylvania.

Returning home in 1947 to spearhead his country's campaign for freedom from Great Britain, Nkrumah would become a vociferous critic of American foreign policy. But he retained a strong penchant for America - as a nation and as a concept. Drawn especially to the civil rights movement and its affirmation of American ideals, Nkrumah hosted Martin Luther King Jr. and other African-American activists at Ghana's 1957 independence celebrations. He also provided a refuge for W.E.B. DuBois, who was hounded out of the United States and is buried in Ghana.

Most of all, Nkrumah admired Americans' optimism, vitality and informal spirit. Ghana was the first country to welcome the Peace Corps, in 1961, and my favorite picture of Nkrumah shows him teaching a popular local dance to Peace Corps volunteers. It's hard to tell who's having more fun.

Nkrumah also imagined Ghana as the vanguard of freedom across the African continent. That's why he adorned the new Ghanaian flag with a black star, which recalled the short-lived shipping line started by the Jamaican pan-Africanist Marcus Garvey. Garvey hoped his Black Star Line would transport black people between the United States, the Caribbean and Africa.

So it's especially fitting that Ghana's Black Stars - yes, that's the name of the national soccer team - should be the only Africans to advance to the quarterfinals, in the first-ever World Cup held on African soil. "We are all Black Stars," declared a headline last week in South Africa's Mail and Guardian, urging Africans everywhere to support Ghana in its remaining contests.

Back in Ghana, meanwhile, all-night dances and prayer vigils marked the victory over the United States. In our land of multiple professional sports and leagues, it's hard to imagine the stranglehold soccer has on the African psyche. In Ghana, I never saw anyone playing, watching or discussing any other sport. When the Black Stars are on the air, giant crowds gather around outdoor televisions, greeting each goal with whoops and horns.

And that, too, is a legacy of Nkrumah. Pouring scarce resources into developing Ghana's national team, he also helped establish the Africa Cup of Nations tournament. Eventually, he predicted, soccer would "earn for our dear continent a greater respectability and recognition at the universal level."

Yet despite some standout players, Africa remains a poor cousin in the soccer family. That's mainly because the continent itself is poor. Forbes magazine recently ranked Ghana's economy as the ninth-worst in the world. How do you field a hot team without cold, hard cash?

Worse, beneath all the hype and horns, many Africans don't really believe they deserve an equal place on the world stage. That's why most of the African national teams (including Ghana's) are still coached by non-Africans. In the current World Cup, only one of the six qualifying African teams had an African coach. Ask people in Africa about this, and they'll mumble something about the non-African coaches' wider "international experience." But dig a bit deeper, and they'll say that the top African stars - who often play professionally in Europe, under white coaches - wouldn't obey a fellow African. Nkrumah must be rolling over in his grave.

But Nkrumah would be proud to see Ghana advance to the round of eight, where it will play Uruguay tomorrow. He would welcome the support of Americans, a people he loved and admired. And he'd be astonished to hear a single bold slogan, resonating across Africa and around the globe: Go Black Stars!