PHILADELPHIA, OCT. 6 -- Mayor W. Wilson Goode and former mayor Frank L. Rizzo traded harsh and highly personal attacks in a televised debate here tonight, with Rizzo accusing the incumbent of "killing 11 people" in the MOVE disaster and Goode calling the one-time police commissioner "a certified liar."

Both men sustained a remarkable level of vitriol during their hour-long face-off, their only televised debate before the Nov. 3 election, as each sought to eviscerate his opponent's record as mayor. Most recent polls show Goode, 48, the sharecropper's son who became the city's first black mayor, leading Rizzo, 67, the ex-policeman who ran the city from 1972 to 1979, by five to 18 points, although both sides expect a tight finish.

Although Rizzo, a Democrat turned Republican, has been trying to project a softer image, he came out swinging tonight, bringing up the 1985 police bombing of MOVE, a radical back-to-nature group, minutes into the debate and injecting it at every opportunity.

"I don't believe Wilson Goode set out to incinerate 11 people, he and his police and fire commissioner, but they did -- {including} five children . . . . Frank Rizzo never killed 11 people," he said. Rizzo said he had been cautious during a 1978 confrontation with the group because "we didn't want to kill anyone, particularly five children."

The Democratic mayor quickly began counterpunching, reminding viewers three times that Rizzo had failed a 1975 polygraph test about whether he had made a back-room political deal. "The only person running for mayor who's a certified liar is Frank Rizzo," Goode said.

The debate at WPVI-TV was seen as crucial in an election that will largely turn on racial voting patterns. Goode won 96 percent of the black vote in last spring's primary and is expected to do so next month; his strategists say he needs 16 to 20 percent of the white vote to win a second term.

Rizzo, who unsuccessfully challenged Goode in a 1983 primary, has a hammerlock on the blue-collar ethnic vote, and both sides say the race will be decided by about 50,000 young, moderate, white professionals.

"To some people, it's a race between a guy they didn't like originally and a mayor they had great expectations for and were disappointed in," said Paul Maslin, Goode's pollster, adding that most voters do not want to return to the "tumultuous" Rizzo era. Said one prominent Republican official: "I think Wilson Goode is the worst mayor in the history of the world, and we put up the only guy who could lose to him."

The candidates are almost polar opposites. Goode is earnest, humorless and hard-working, a low-key man of few words; Rizzo is barrel-chested, profane and impulsive, a backslapper who loves to spin stories.

In the debate, Goode was contrite about the MOVE disaster, saying: "I will carry deep down in my heart a scar for the rest of my life. Nothing I can do or say will bring those 11 people back." But he said that unlike Rizzo, he was able to admit his mistakes.

"His entire eight years was a disaster -- high taxes, cronyism, the loss of respect for this city . . . police brutality," Goode said.

The mayor stumbled over a question about why he had accepted nearly two dozen free suits from a union leader, saying he later paid for the suits after a federal probe began. Rizzo ridiculed his account, saying, "Wilson Goode stands here and lies."

But Rizzo rambled in some of his attacks. Talking about police confrontations in the 1970s, he inexplicably said, "Frank Rizzo wasn't police chief of New York when that burned to the ground." He also made an unsubstantiated charge that some Goode relatives may be on the city payroll.

As for the polygraph incident, Rizzo said he "told the truth," but did not elaborate.

Rizzo frequently returned to Philadelphia's waste-disposal problems. He declared that "the streets are filthy" and said he would "solve the trash problem in 90 days," but never said how.

Goode, speaking in a more controlled style and peppering his remarks with statistics, said that Rizzo "did nothing" about trash during the 1970s other than make sweetheart settlements with the sanitation workers' union. But Goode, beset by an image as an inept administrator, could not explain why he has failed to win city council approval for a $260 million trash-to-steam plant.

During a three-week television advertising blitz, Rizzo has appeared surrounded by children (to show his support for day-care centers) and ballerinas (to promote himself as a patron of the arts). The man who once said he would make "Attila the Hun look like a faggot" also was seen admitting past mistakes and talking about gay rights.

"We're not repackaging him," said Elliott Curson, Rizzo's media adviser. "We're showing aspects of Frank Rizzo the public didn't know about." As for Rizzo's reputation as a polarizing force, Curson said, "Rizzo is Rizzo, but the city worked under Rizzo."

Tonight, however, Rizzo was twice unable to answer a question about how he had mellowed since his years as mayor. He appeared more comfortable on the attack, reminding viewers that Goode had handpicked a black developer with a history of bankruptcy to rebuild the 61 row houses destroyed in the MOVE bombing.

A grand jury, accusing Goode of "gross mismanagement," has charged the developer with stealing $208,000, adding to the project's delays and cost overruns.

Goode's campaign has sought to deflect the focus on his mistakes by reminding voters of what they disliked about Rizzo's tenure, exhuming charges of corruption, police brutality and, Goode said last week, "racism."

"There is not one issue Rizzo can bring up -- taxes, corruption, city services -- that he is not vulnerable on himself," a top Goode strategist said. "Rizzo talks about trash a lot, but he doesn't have a plan. All he does is talk about MOVE."