After months of attacking each other from afar, Mayor Bloomberg and his Democratic opponent, Fernando Ferrer, on Sunday will face off in their first debate.

The debate, to be aired on WABC at 9 a.m., comes less than two weeks before the November 8 election. With recent public opinion polls showing Mr. Bloomberg enjoying a commanding 31-point lead, the candidates must accomplish very different objectives during the hour-long program, political analysts said. Mr. Bloomberg needs to create as little news as possible and ride out his strong approval ratings, while Mr. Ferrer must generate news and create some momentum before the election, analysts said.

“If Michael Bloomberg behaves himself, if he doesn’t blow up, and if he doesn’t commit a truly gargantuan gaffe, he’s done what he needs to do,” a public affairs professor at Baruch College, David Birdsell, said. “Freddy Ferrer needs to push Mike Bloomberg off message and prompt the kind of news that leads to competitive stories in the final week of the campaign.”

Mr. Birdsell said Mr. Ferrer “has very little to lose and can afford to be aggressive.”

Earlier this month, Mr. Ferrer along with the Conservative Party candidate, Thomas Ognibene, and a number of African-American leaders criticized Mr. Bloomberg for skipping a debate at the famed Apollo Theater in Harlem hosted by the city’s Campaign Finance Board. Mr. Bloomberg, a billionaire who is financing his own campaign, does not participate in the board’s program or accept matching funds and is therefore not required to follow its rules.

Instead, his campaign announced that it would participate in only two debates, one on Sunday, which isn’t affiliated with the CFB, and the other on Tuesday, which is. The mayor’s decision to wait until this late in the campaign gives his opponent less wiggle room to change the political landscape.

To compound matters, the Sunday morning time slot, which until last week was when “This Week With George Stephanopoulos” aired, gets only about 200,000 viewers in the New York-New Jersey area, according to a vice president of research for ABC, Pat Liguori.

If the Democratic primary debates are any indication of what’s to come, questions will likely focus on the candidates’ proposals for education, health care, security, and Lower Manhattan redevelopment. What hasn’t received as much attention are the candidates’ plans for dealing with the looming $4 billion deficit and where budget cuts would be made. A senior adviser to Mr. Bloomberg, William Cunningham, was tight-lipped about how the mayor was preparing for the debate. “He doesn’t have somebody mimicking the opponent,” Mr. Cunningham said. He said the mayor would simply refer to his record and to his plans for the future.

Earlier this month, the New York Post reported that the speaker of the City Council, Gifford Miller, who ran unsuccessfully in the Democratic primary, was playing the mayor in practice debates with Mr. Ferrer.

The Democratic nominee in the 2001 mayoral race, Mark Green, debated Mr. Ferrer in a runoff election that year and Mr. Bloomberg in the general election.The debates with both candidates were combative. Yesterday, Mr. Green, who endorsed Mr. Ferrer in this election, said he expects both men to exceed expectations.

When asked what advice he would give to the candidates, he quipped, “Don’t cry at any point in the debate.”