LOS ANGELES -- Last November, when Mervin Field's California Poll reported Dianne Feinstein 18 percentage points behind in her race for the Democratic gubernatorial nomination, the usually optimistic former San Francisco mayor began to wonder if things could get any worse.

Her campaign was sidelined for several weeks as she recovered from a hysterectomy. Her campaign consultant quit and told everyone she was lazy. The secretary of a labor leader she telephoned for support asked her to spell her name and inquired, when Feinstein said she was running for governor, "governor of what?"

Feinstein recalled telephoning Field, a San Francisco-based pollster she had known for years, and asking "if he thought there was any way of reversing it, and the sum and substance of what he said was, it had never been done before."

"That was the turning point for me," she said in an interview last week after becoming the first woman to win a major party's gubernatorial nomination in California. "When I'm really down, I fight."

Some analysts have begun talking about Feinstein, almost 57, as a potential savior of the national Democratic Party. If she can beat the Republican nominee, Sen. Pete Wilson, in November, her party would suddenly have as governor of the most populous state a political property unlike any it has seen in some time. Her admirers believe Feinstein's blend of social consciousness, toughness on crime and fondness for free enterprise could, combined with her appeal to women, could unite white Miami businessmen and black Detroit welfare mothers into an unstoppable national alliance.

Skeptics and her many critics warn of perils ahead. Wilson matches her record on almost every issue: He supports abortion rights, the death penalty, business and the environment. Wilson is two months younger and served two more years as mayor of San Diego (11) than Feinstein served in San Francisco (nine). He may raise $20 million to her expected $10 million and will not have to answer questions that have been put to Feinstein about her dependence on the fortune of her financier husband Richard Blum, source of nearly $3 million in Feinstein campaign funds so far.

Few who have watched her give a speech, or handle a television debate, or work her way through a crowd doubt she beats Wilson as a campaigner. At 5 feet 10 inches, she is one of the tallest women in American politics, and combines an expensive wardrobe with hugs and small talk that many find appealing.

State Sen. Quentin Kopp, an independent who lost a mayor's race to Feinstein in 1979, calls her "the luckiest woman I have ever known" but acknowledges she is "eloquent" and was "able to project herself as an individual personality" in a way that overwhelmed her primary opponent, state Attorney General John Van de Kamp.

At a primary campaign stop in Hawthorne, a tattered Los Angeles suburb full of upwardly mobile blacks and Hispanics, Feinstein mesmerized a gathering of Democratic women with smiles, attention to babies and the elderly and a lengthy farewell in which she ignored aides looking at their watches so she could lead the Hawthorne High School band and have her picture taken with its members. Given Feinstein's patrician bearing, it was as if a visiting countess had taken up rock guitar, but the audience loved it.

At Hawthorne, Feinstein repeated a theme Wilson seems ready to turn to his advantage. "We have pledged to appoint women in proportion to their parity in the population, 50 percent plus," she said, "to appoint people of color in proportion to their parity of the population," including a 25 percent goal for Hispanics. Angry letters to the Los Angeles Times called this a plea for quotas, which she emphatically denied.

"I've been opposed to quotas because quotas are generally used to keep people out," she said, adding that she would appoint judges and cabinet members on merit but expected her administration "to be reflective of the community at large."

Wilson aides are examining her record as mayor for evidence of the sort of avant-garde liberalism that hurt Feinstein's image at the beginning of the primary campaign. Kopp said this search will bear fruit. "She's a tax-and-spend liberal," he said. "She once favored legalizing prostitution."

Feinstein engineered the greatest reversal of poll standings in a California primary with a riveting 30-second commercial that emphasized quite the opposite. "I think I am different," she said last week. "I think I believe very much in the center of the political spectrum. I believe there are certain areas of life that take conservative solutions. I think law and order is one of them." Her death-penalty support, she said, broke through the "stereotypical barrier" that women are soft on crime.

Feinstein is often unpredictable, a trait voters find charming and campaign managers exasperating. She refused to endorse Lt. Gov. Leo McCarthy (D) in his 1988 attempt to unseat Wilson from the Senate because McCarthy opposed (and Wilson supported) her efforts to have the battleship USS Missouri based in San Francisco. Last week, with McCarthy at her side, Feinstein apologized and called the dispute a fight "between brothers and sisters."

As mayor, Feinstein often enraged unions and other Democratic allies with budget cuts and opposition to pay increases. Her answers to campaign questions often diverge from Democratic writ. Questioned before a Chinatown fund-raiser about President Bush's support for most favored nation trading status for China, she spoke of the need to maintain links with Beijing and declined to join other Democrats, such as San Francisco Rep. Nancy Pelosi (D), in opposing Bush.

Feinstein's telegenic campaign skills are often compared to Ronald Reagan's, but, unlike the former president, she loves detail work and resists long vacations. She put off removal of the benign uterine tumors that led to her hysterectomy because, she said, "I didn't want to take the time off while I was mayor." She unexpectedly became mayor in 1978 after the murder of mayor George Moscone.

Despite her wealth -- she and Blum declared a $7 million 1989 income -- Feinstein's rhetoric embraces the middle class and the working class who want to become middle class. Her speeches are full of talk of comfortable houses, safe streets and good schools.

When admirers call her an automatic contender for national office if elected governor, she does not use the common "I-am-thinking-only-of-thiselection" response. Clearly, she has thought of it.

"I think if I'm elected governor, and I do a good job over a period of time, that may be true," she said. "But I think it depends on the job I do as governor. I don't think just winning it makes me automatically a contender."