THE San Francisco mayoral race has entered the final turn with a latecomer making her way through the pack.City supervisor Angela Alioto, daughter of former Mayor Joseph Alioto, has moved past three Democratic rivals to within striking distance of incumbent Art Agnos: 28.7 percent for Agnos, 21.7 percent for Alioto (with an error factor of plus or minus five points), according to a San Francisco Examiner/KRON poll. Ten candidates are challenging Mayor Agnos (D) in the Nov. 5 election, with a runoff expected between the top two vote getters on Dec. 3. Miss Alioto entered the race Aug. 8. Pollsters say her support has been taken directly from the three other Democratic contenders - former Police Chief Frank Jordan (13.7 percent); Supervisor Tom Hsieh, a Beijing-born architect (6.7 percent); and former sheriff and supervisor Richard Hongisto (5.7 percent). Five other candidates - including a Republican and two sociali sts - are given no chance of winning. "At the moment, Alioto is the name to beat in second place," says Larry Kamer, a political analyst at Kamer/Singer Associates. While polls show Agnos's popularity has declined since taking office in 1987, most feel he will win a closely contested runoff. Pollster Richard Hertz says the race is "so volatile it is impossible to call. Half the respondents said they might change their mind before election day." For several months, the election has had a relatively low profile across the city. Candidates Jordan, Hsieh, and Hongisto - and now Alioto - have leveled salvos at Agnos by harping on a declining quality of life: loss of business clout and population; decaying infrastructure; increases in crime, filth, homelessness. But the election battle is coalescing. A major televised debate sponsored by the League of Women Voters has helped voters to comparison-shop. The recent veto by Gov. Pete Wilson of a bill that would have outlawed job discrimination against homosexuals has brought gay issues into the election forefront. And new polls showing Alioto as a serious challenger have brought steady pressure from media over her controversial personal and campaign finances. One newspaper questioned salary advances from her father's law firm that she spent on a 1986 campaign for the board of supervisors. Another disclosed huge loans taken against her property, questioning whether she could repay such debt on her income as a lawyer and supervisor. "It seems she has one of two problems," asserts Mr. Kamer. "Either violations of campaign law or failures to report income." But even with the burgeoning attention, the election is being called pedestrian, with a lack of any truly strong candidates. "There are not many old-style civic leaders left in San Francisco," says commentator and media analyst Richard Rapaport. "I'm not sure anyone in this race understands the dynamic of a city and how to lead." Much of the current campaign revolves around attacks on Agnos personal style. "When he's not aloof, he goes out of his way to be abrasive," says Tom Hsieh, who had been an outspoken critic for years before becoming a mayoral candidate. Lauded for his charm, Agnos won much credit for moving quickly after the earthquake of 1988. But he has been taken to task for the general decline many feel has hit all California cities: national recession; drought; state and federal cutbacks in urban aid. But Agnos has tried to mitigate such criticism by admitting past mistakes. Now, eyes are turned to Agnos, Alioto, and Jordan in what many see as a three-way race. Agnos is seen as relying on his superior charm and incumbency. Jordan and Alioto are playing on returning the city to its earlier appeal as a world-class city. Besides joining a demonstration protesting Governor Wilson's veto of legislation banning discrimination against gays and lesbians, Jordan has trumpeted his 33-year career in community relations. Alioto has focused on homelessness - advocating increased city funds for smaller, in-home facilities, and criticizing Agnos's programs to build large shelters.