She began with less money, less name recognition, no power base. She had never won public office, never run for public office, never led in opinion polls -- not even at the end.

But she had a theme: Clean house.

And last night, propelled by her home town's unhappiness with four politicians it already knew, Sharon Pratt Dixon leaped out of her car at 16th and U streets NW and thrust a fist into the night air at the first radio flash that she had been anointed as the Democratic Party's nominee for mayor of the District of Columbia.

"Let's clean house!" supporters cried during the first of Dixon's two appearances in the ballroom of the Park Hyatt Hotel, where she claimed victory at 12:20 a.m. "Let's clean house! Let's clean house!"

"I just had an instinctual sense we were going to do it," Dixon had said earlier in her three-room suite at the hotel as 25 delirious aides celebrated and a makeup artist worked on the candidate for television appearances. "I just felt from the beginning the city was ready for change. It wasn't as apparent to others as it was to me. I just didn't see anybody else who was offering change. I just felt at some point we were going to prevail."

As she left the room to make her victory appearance, Dixon encountered Arrington Dixon, her former husband and former chairman of the D.C. Council, who hugged her and lifted her off the floor. "Wonderful job, baby," he said. He had spent the day campaigning for her in a precinct in Ward 8.

It was a Hollywood finish to a 505-day campaign from nowhere in which the 46-year-old divorced mother of two daughters never strayed from a refrain of new blood, contrasting herself with three opponents who have served in the D.C. Council for years and one from the halls of Congress.

The political pros, she said last night, just never got it: "They have as much vision as their last experience. They tend not to recognize change when they see it. They measure everything from the existing power structure."

She added, "I wanted it to happen this way. It's the only legitimate way."

All day yesterday, she sensed what was coming, from morning coffee in the kitchen of her home in Ward 4 through her hopscotch visits to precinct after precinct. Campaign volunteers cheered her, voters applauded her, even a worker for rival Charlene Drew Jarvis shook her hand and said, "I can live with you."

"I had people walking by all day saying, 'I'm praying for you,' " she said last night. "The first time I got nervous was one minute past 8" -- one minute after the polls closed -- "because it was out of my hands now."

Arriving at the Park Hyatt at 24th and M streets NW, Dixon hugged volunteers and planted a lipstick-red kiss on the forehead of her father, Carlisle E. Pratt, a retired D.C. Superior Court judge who now uses a wheelchair because of a stroke.

Inside the hotel's ballroom, Florence Tate, one of the campaign's volunteer public relations aides, pointed out several workers who began with the candidate months ago.

But most hadn't. Tate was asked: Who do you see here who has just signed on as a Dixon supporter?

"Well, practically everybody just joined," Tate said. "When I started full time with the campaign a month ago, we had no phone bank, no photocopier, no coffee pot."

Upstairs in her third-floor suite, Dixon was still answering the phone herself until, swamped by congratulatory calls, she unplugged it.

She said her campaign against Republican nominee Maurice T. Turner Jr. would not be easy. But she already is talking like Mayor Dixon.

"I'd like to begin some change in the first year," she said. "By three years, we should see a marked difference. By five to six years, we should be really humming, but we may be able to do even better than that."

She was already talking like ex-mayor Dixon too: "I intend to introduce legislation to limit the mayor to two terms. I think it's unhealthy. I think it's too much power. We need to encourage turnover."

Dixon, who seemed cool amid the chaos of victory, said she expected her four opponents to close ranks behind her because "all of us indicated throughout the campaign that our bottom-line commitment was to the city."

Noting that another outsider, Harold Brazil, won a seat on the D.C. Council, Dixon said, "I always thought the 'clean house' would have a coattail effect."

Downstairs, there was no such cool.

Standing in the middle of the crowded, noisy ballroom, with music blaring in the background and people almost yelling to hear each other, Stephanie Greene tried to describe the evening.

Greene started with Dixon in April of last year, when there were no more than eight campaign workers.

"We were told time and time again that this woman could not win. That she had no organization, no money and that she was too strident," said Greene.

"Then the city started to embrace her. And now this. That's the euphoria I feel tonight. Tonight is truly a dream."

Supporters in the ballroom included old and young, casual and dressy, black and white. They danced. They sang. Two campaign workers, Barry Hargrove and Annaliese Bruner, twisted and turned, doing what they described as the Jerk and the Mashed Potato. "We're feeling real up even though we've been working since 7 a.m.," Bruner said.

Over in another corner of the ballroom was a huddle of three: Amy Slummer, a law student and a Dixon campaign worker; Everett Bellamy, dean of Georgetown Law School and a financial supporter of Dixon's; and Craig Mendelsohn, a physician and friend of Amy Slummer's.

Slummer said that she had been "real surprised at how well Dixon has done."

Yet while Dixon portrayed herself as the only outsider in the mayor's race, she is no political novice.

For 12 years, she served on the Democratic National Committee and was its treasurer. She ran the unsuccessful 1982 mayoral campaign of Patricia Roberts Harris.

Still, she was no match in recognition for the four people who came to be her opponents: D.C. Council Chairman David A. Clarke, council members Jarvis and John Ray, and D.C. Del. Walter E. Fauntroy.

Vowing to cut 2,000 middle-level management jobs from city government, vowing to restore integrity in the wake of Marion Barry's problems, calling the council members "the three blind mice" who had seen, heard and done nothing about the condition of the city, Dixon took an aggressive, almost angry style to the city, and it clicked.

But why run?

"I think about it now," she said recently, "about what does drive me. Some of it is the odds. The world is full of people who write people off, and that's why I always admire a fighter, someone who beats the odds."

Staff writer Molly Sinclair contributed to this report.