Incumbent Thomas M. Menino, once derided as Boston's "accidental mayor", handily defeated challenger Maura Hennigan on Tuesday to win a fourth term as mayor, setting his sights on becoming the city's longest-serving chief executive.

With 99 percent of precincts reporting, Menino coasted to victory, receiving 68 percent of the vote to Hennigan's 32 percent, unofficial results showed.

Hennigan telephoned Menino before 10 p.m. to concede, according to her spokeswoman.

It was a sweet victory for the lifelong Boston resident after a sometimes testy battle for the city's top political office.

"I think we'll have great opportunities in the fourth term and we're going to use those opportunities," he told reporters. "It's a great time for me, an exciting time, very few people have this opportunity."

Hennigan did not immediately emerge to address supporters who had gathered at another downtown hotel.

Menino, 62, began the day casting his ballot at an old city archives building in the Hyde Park neighborhood before setting off on a daylong tour of the city. He arrived at an election night party at the Fairmont Copley Plaza in Boston just before polls closed at 8 p.m.

A 14-piece band serenaded Menino supporters who congratulated each other and watched on large screens as photographs flashed showing the mayor campaigning around the city.

Hennigan, 53, began the day casting her ballot at the Joseph Manning School in the Jamaica Plain neighborhood. She also embarked on a whirlwind tour of the city, shaking hands at polling locations across the city before heading to her campaign party at the Back Bay Hilton.

Until the end, Hennigan held out hope for an upset win.

"We hope we're going to have a great turnout," Hennigan said earlier in the day. "I believe at the end of the day they will choose new leadership, new vision for the city of Boston."

Both candidates had a lot riding on the campaign. Menino was shooting for the record books while Hennigan, a longtime city councilor, wanted to become Boston's first woman elected mayor.

Menino, whose reputation for garbled speech won him the nickname "Mumbles," has built a reputation focusing on nuts and bolts in The Hub -- fixing potholes, cleaning streets, even banning the age-old practice of saving a shoveled-out parking space by putting folding chairs or trash cans along the curb.

Menino is on the verge of setting the record as the city's longest-serving mayor if he serves out another four-year term, which would be his fourth. Kevin White also served four terms, from 1968 to 1983, but Menino served an additional four months as acting mayor after his predecessor, Raymond L. Flynn, left office in 1993 after being named ambassador to the Vatican.

That propelled Menino from president of the city council to the mayor's office. Critics labeled Menino the "accidental mayor," but Menino never looked back.

Hennigan, who faced an uphill battle, attacked Menino for lackluster school performance and rising housing costs. She also accused Menino of not doing enough to prevent the 2004 death of a college student hit in the eye with a police pepper-spray pellet during a celebration by Boston Red Sox fans outside Fenway Park.

At a polling place at City Hall, Brian Adams, 49, cast a vote for Hennigan.

"I'm not thrilled with either one of them, but I think incumbents shouldn't go unchallenged," he said.

John T. Stanton, 78, voted for Menino because he thinks the mayor is doing a good job promoting affordable housing and guiding citywide development.

"He seems to have a good approach to doing business for the city," he said.

One of the campaign's oddest controversies cropped up when the Hennigan campaign launched a television ad mocking Menino for "ducking the issues." The ad used drawings similar to those in the children's classic "Make Way for Ducklings" set in Boston. That, in turn, drew fire from critics who said the book should be off limits in a political campaign.

With 99 percent of precincts reporting, Michael F. Flaherty, Felix D. Arroyo, Sam Yoon, and Stephen J. Murphy seemed headed to win the four at-large city council seats in Boston. Yoon would become the first Asian American to win a council seat. Patricia White, daughter of former mayor Kevin White, and Edward Flynn, son of former mayor Ray Flynn, trailed near the end of the pack of eight candidates for four seats.