Mayor Nutter on Tuesday defeated T. Milton Street Sr., the brother of his political nemesis and predecessor, making it all but certain that he will serve another four years as Philadelphia's mayor.

In unofficial returns with nearly 93 percent of the precincts reporting, Nutter captured 76 percent of the vote to Street's 24 percent.

Nutter addressed supporters at a victory gathering at the Radisson Plaza-Warwick Hotel in Center City, standing inside the same ballroom where he celebrated his first win as a reformist candidate in 2007.

Nutter, who took the stage with his wife, Lisa, by his side, dismissed the notion that the 24 percent vote that Street captured had any meaning beyond signifying tough economic times.

"This is a business in which you either win or you lose," said Nutter.

In the Republican mayoral primary, challenger John Featherman was tied with the endorsed candidate, Karen Brown.

While Nutter will face one of them in November, Philadelphia's 6-to-1 Democratic registration edge virtually assures him of re-election.

The campaign was far different than Nutter's first, drawing little attention as reflected in the low turnout of voters. Nutter and Street appeared together at no candidate forums, and there were no campaign debates.

By contrast, Nutter's late surge to victory in 2007 followed what seemed to be a record number of forums and debates among the five major Democrats running, with Nutter emerging as the candidate most able to foster change.

Well before Election Day, Nutter was aware of the lack of voter enthusiasm in general. He noted that the city's unemployment rate was 5.6 percent when he took office, peaked at 11.9 percent last summer, and is 10.2 percent now.

"People are angry about a lot of stuff," he said. "And when it comes to elections, they are going to do something" - and he said that has affected executive officeholders like himself.

In 2009, Seattle's mayor lost his primary bid for a third term, and New York City's mayor won his third-term election by a margin of less than 5 percent. In 2010, Washington's mayor lost his primary race, and two months ago, the mayor of Kansas City finished third in his primary.

Willie Lundy, a poll inspector at Seventh and Norris Streets, blamed low voter turnout on apathy.

"Nutter? People don't care about Nutter," he said. "People are worried about their jobs. People are worried about their bills, their family and their children. That has been the feeling throughout the city. Nobody is enthuastic about this election."

Nutter nonetheless garnered support.

Voter Zakia Robins wasn't sure who her Council candidate was, but was clear on her vote for Nutter.

"You have to give people time to fix mistakes," Robins said of the mayor. "Everyone can say how someone else would be better, but. . .." Robins paused, then sighed. "Give him four more years."

Thomas Heary, 51, a civil engineer, said he voted for Nutter because "absolutely no way would I want a Street as mayor." T. Milton Street, Heary said, "doesn't even pay his bills. Why should he be mayor?"

Heather Diocson, 39, a committee person from Street's own 62d Ward, said she voted for Street because she disliked Nutter.

"He has rolling blackouts and police layoffs," she said. (No police have been laid off.) "Libraries and rec centers are closing," she added. (No libraries or recreation centers have closed.)

While Nutter ran radio ads and campaigned more heavily in the closing days, he did not air any television commercials. Partly because of that, he still has nearly $1.3 million in the bank - a small but important sum of money that would become vital if former mayor and newly registered independent John F. Street, or anyone else, decided to launch a last-minute challenge to Nutter in the November general election.

Nutter will for sure face a GOP nominee, either Karen Brown, a former Democrat backed by the city's Republican Party, or John Featherman, a Realtor. The results were too close to call with 65 percent of the precincts reporting.

In the row offices, Jewell Williams captured the Democratic nomination for sheriff with 61 percent of the vote. That's with two-thirds of precincts reporting.

With several potential candidates, including City Councilman Bill Green and State Sen. Anthony Williams, deciding not to run this year, Nutter looked to be the city's third straight mayor waging an uncontested reelection campaign.

That changed in February when Street, an ex-convict who owes the city nearly $400,000 in taxes, announced he was running to give a voice to those who are ex-offenders or impoverished. Shortly afterward, Nutter mounted an unsuccessful effort to knock Street from the ballot by challenging his nominating petition.

Street spent election night at the headquarters of AFSCME District Council 33, a 9,400-member city union that backed him.

Nutter would begin a second term with a higher national profile since he is in line to become president of the U.S. Conference of Mayors next May or June. He is also slated to lead the organization, which promotes the needs of cities, just as President Obama is expected to be seeking reelection.

At the same time, Nutter's second term would include many of the same problems he faced in his first: finding a long-term fix to the city's costly pension system, settling contracts with two municipal unions that represent more than half of the city's workforce, and changing the corporate tax structure.

And at least one ongoing challenge has worsened - the pool of available public education dollars has shrunk.

Nutter declined an interview before the primary election about his second-term goals. But in an interview two weeks ago with The Inquirer's editorial board, he painted a vision of a vastly different four years - beginning with his own leadership.

"In some instances, it will be no more Mr. Nice Guy," he said, adding that there were "times I could have been tougher."

For most of his term, Nutter had an uneasy relationship with Council. But that would change with the election of many of his slate of candidates, as it may eliminate a potential roadblock to his second-term agenda. In addition, Nutter is working to help an ally, Councilwoman Marian B. Tasco, become the new Council president in January.

Inquirer staff writers Kia Gregory, Melissa Dribben, and Miriam Hill contributed to this article.