HOUSTON (Reuters) - Houston Saturday became the first major U.S. city to elect an openly gay mayor, Annise Parker, after a hotly contested run-off election that gave gay and lesbian supporters a symbolic victory following defeats over legalizing same-sex marriages in California and Maine.

Traffic flows at dusk with the downtown Houston skyline in the background as night falls on America's fastest growing large city October 3, 2008. REUTERS/Richard Carson

“The voters of Houston have opened the door to history,” Parker told supporters at a convention center in Houston. “I know what this win means to many of us who never thought we could achieve high office.”

A Democrat who is now the city controller, Parker will face a $130 million budget deficit when her term as mayor begins in early January.

She won the run-off against fellow Democrat Gene Locke, an African-American lawyer and former city attorney, after a four-way primary in November came up inconclusive.

Last year California passed a same-sex marriage ban known as Proposition 8 and Maine voters in November overturned a state law allowing same-sex marriages.

Other big U.S. cities like Portland, Oregon and Providence, Rhode Island have openly gay mayors, but none the size of Houston -- the fourth-biggest city in the nation with over 2 million residents. Abroad, Berlin and Paris are among cities with gay mayors.

Houston is a Democratic stronghold, but Republicans have dominated state and national elections since George W. Bush won a gubernatorial contest against Democrat Ann Richards in 1994.

“Most peoples’ understanding of Texas would not be this open and this welcoming,” said Chuck Wolfe, president of the Gay and Lesbian Victory Fund. “But the people of Houston obviously don’t feel that way.”

Parker was opposed by conservative religious groups and anti-gay activists.

Houston voters are concerned less with lifestyle issues and more with bread-and-butter issues like the budget, public safety and city services, said Bob Stein, a political science professor at Rice University in Houston.

“Voters don’t think it’s germane to city politics,” said Stein, referring to the same-sex issue. “They think city government’s about picking up the trash.”

Term limits bar Bill White, Houston’s current mayor, from seeking re-election. White says he will run for Texas governor in a race in which Texas Gov. Rick Perry and U.S. Senator Kay Bailey Hutchison will square off for the Republican nomination next year.